Mercedes S-Class W-140

1991-1999 of release

Repair and operation of the car

Diagnostics of malfunctions

The description of diagnostics of electronic control systems and diagnostic codes are provided in the Head Elektrooborudovaniye of the engine.

In this Section the simplest scheme of clarification of the reasons of the malfunctions and refusals happening in knots and systems of the vehicle is offered. Refusals and their possible reasons are broken into groups on a sign of the relation to certain components or systems of the car, such as the engine, the cooling system, etc., besides, in the text references to Chapters and Sections concerning these problems are given.

Remember that the successful completion of search of causes of defect is not the black magic available only to skilled professional mechanics at all, and is defined by a combination of a certain knowledge and patient, systematic approach to a problem research. It is necessary to move always from simple to difficult, to bring each check to the logical end and to try not to pass the obvious facts - everyone can forget to fill fuel in the fuel tank or to leave included in lighting fixtures for the night.

And at last, it is always necessary to try to make a clear picture of development of malfunction and to take the corresponding steps for prevention of a recurrence. If the failure of electric equipment happened for a cause of infringement of quality of contact, check a condition of all other contacts and electric sockets of system at the same time. If the same safety lock several times in a row continues to fuse, there is no sense in its further replacement - it is necessary to try to find out a cause of failure. Remember that failure of a minor component can be a sign of violation of functioning of more important knot or the whole system.

The engine is not turned in attempts of its start

1. Corrosion of plugs of the battery takes place or fastening of tips of wires on them weakened. Check a condition of plugs and tips. Tighten terminal clips, if necessary remove corrosion traces.
2. The battery is discharged or faulty. If tips of wires are found by pure and reliably fixed on battery plugs, turn the ignition key in position of ON, then include head headlights and/or screenwashes. If this electric equipment does not function, the battery is discharged.
3. Transmission it is inexact it is established in situation "P".
4. Conducting in a chain of system of start is torn off or fastening of wires on plugs weakened. Check a condition of rovod, plugs and electric sockets of the battery, traction relay of a starter and the lock of ignition.
5. The gear wheel of a starter is jammed in a gear wreath of a driving disk. Try to turn the engine for a crankshaft pulley. At the first opportunity remove a starter and check a condition of a gear wheel and a gear wreath.
6. The traction relay of a starter is faulty (see the Head Elektrooborudovaniye of the engine).
7. The starter is faulty (see the Head Elektrooborudovaniye of the engine).
8. The ignition lock is faulty.

The engine is turned, but not started

Petrol models

1. Start is incorrectly made (see appropriate section of the Head the Operation manual).

Order of start of the petrol engine

Stability of operation of the engine on single turns is broken

Petrol models

1. Depression losses take place. Make sure of reliability of an inhaling of fixing bolts / nuts, check the fact and quality of fastening on the unions on the inlet pipeline of all vacuum hoses. Wiretap the working engine by means of a stethoscope or a piece of a fuel hose. Existence of the hissing sound will allow to reveal a source of "leak" of vacuum. It is possible to use solution of soap water for check not less effectively.
2. Malfunction of components of a power supply system or electric equipment takes place (see Chapters of the Power supply system and release and engine Electric equipment).
3. The valve of system of the operated ventilation of a case is blocked (see the Head Dvigatel).
4. The air filter is blocked (see the Head of the Power supply system and release).
5. The fuel pump does not provide giving of enough fuel to injectors of system of injection (see the Head of the Power supply system and release).
6. Leaks through laying of a head of cylinders take place. Perform measurement of compression pressure in engine cylinders.
7. Working ledges of cams of the camshaft are worn-out (see the Head Dvigatel).

Diesel models

1. Quality of connections of fuel hoses on TNVD and the fuel filter is broken. Replace fuel hoses, fix them by collars, tighten screws of angular connections.
2. Fastening of TNVD is mechanically damaged or weakened. Check fastening.
3. Are mixed by junctions of the returnable pipeline and pipeline of supply of fuel. Put connections on the places. The screw of connection of the returnable pipeline has marking of "OUT".
4. Damage to the line of supply of fuel takes place:
      a) Pipelines or hoses are mechanically damaged or littered, - clear fuel pipelines;
      b) The fuel filter is littered. Replace the filtering element.
      c) It is necessary to check the filter and pipelines for availability of ice or wax in the winter, - drive the car into the heated garage, add to system of gasoline;
      d) Ventilation of a tank or the mesh filter of a toplivozabornik is littered, - clean.
5. Adjustment of the beginning of supply of fuel is brought down. Check, make adjustment.
6. Nozzles are faulty. Check. Turn off consistently cap nuts - at an otvorachivaniye of a nut of the faulty cylinder turns of the engine will not fall.
7. The fuel pump of high pressure (FPHP) is faulty. Establish new, or obviously serviceable TNVD for check.

Admissions of ignition on single turns take place

1. Spark plugs are worn-out or polluted or the candle gap is incorrectly exposed (see the Head Elektrooborudovaniye of the engine).
2. Malfunction of components of a power supply system or electric equipment takes place (see Chapters of the Power supply system and release and engine Electric equipment).
3. Wires of spark plugs are faulty (see the Head Elektrooborudovaniye of the engine).
4. Low-quality fuel is filled. The fuel filter is hammered.
5. Losses of depression in the inlet pipeline or through hose connections take place.
6. There is not enough, or compression pressure in cylinders is distributed unevenly. Perform measurement of a compression (see the Head Dvigatel).
7. Violations in work of a control system of the engine take place.

Admissions of ignition take place during the movement on transfer

1. The fuel filter is blocked or pollution of a power supply system takes place (see the Head of the Power supply system and release).
2. Spark plugs are faulty or polluted or the candle gap is incorrectly exposed (see the Head Elektrooborudovaniye of the engine).
3. Malfunction of components of a power supply system or electric equipment takes place (see Chapters of the Power supply system and release and engine Electric equipment).
4. Defect of candle wires takes place (see the Head Elektrooborudovaniye of the engine).
5. Components of systems of decrease in toxicity of the fulfilled gases are faulty.
6. There is not enough or compression pressure is distributed between cylinders unevenly. Remove spark plugs and perform measurement of compression pressure (see the Head Dvigatel).
7. The system of ignition is faulty (see the Head Elektrooborudovaniye of the engine).
8. Losses of depression on the throttle case, the inlet pipeline or through vacuum hoses take place.

The engine spontaneously becomes deaf

1. Adjustment of turns of idling is broken.
2. The fuel filter is blocked and/or moisture or dirt got to a power supply system (see the Head of the Power supply system and release).
3. The refusal of components of a power supply system or sensors takes place (see the Head of the Power supply system and release).
4. Components of systems of decrease in toxicity of the fulfilled gases are faulty.
5. Spark plugs are faulty or polluted or the candle gap is incorrectly exposed (see the Head Routine maintenance). Also check a condition of candle wires (see the Head Elektrooborudovaniye of the engine).
6. Losses of depression on the case of a throttle or through vacuum hoses take place.

The engine does not develop full capacity

1. Malfunction of components of a power supply system or electric equipment takes place (see Chapters of the Power supply system and release and engine Electric equipment).
2. The air cleaner is littered. To clean or replace.
3. Spark plugs are faulty or the candle gap is incorrectly exposed (see the Head Routine maintenance
4. The ignition coil is faulty (see the Head Elektrooborudovaniye of the engine).
5. AT liquid level does not conform to requirements (see Chapters Routine maintenance and Automatic transmission).
6. Transmission revolves (see the Head Stsepleniye).
7. The fuel filter is blocked and/or dirt/moisture got to a power supply system (see the Head of the Power supply system and release).
8. Fuel not of that grade is filled. Fill in in a tank fuel with the required octane number.
9. The adjusting valve of a turbocompressor is damaged
10. The activator of the camshaft of shift of phases GRM is faulty
11. Compression pressure, insufficient or uneven on cylinders. Perform measurement of a compression which analysis of results allows to reveal existence of leakages of valves and/or violation of tightness of laying of a head of cylinders (see the Head Dvigatel).

In addition for the diesel engine

1. The air cleaner is littered. Clean or replace.
2. Uneven supply of TNVD fuel on cylinders. Adjust on the heated-up engine.
3. The moment of the beginning of supply of TNVD fuel is incorrectly determined. Establish.
4. The fuel filter or TNVD (nozzle) is littered. Wash out the preliminary filter, replace an element of the filter of thin cleaning, clean a spray or replace the pump (nozzle).
5. Adjustment of the maximum frequency of rotation of a bent shaft is broken.

There are cottons in system of an admission or shots in system of release

1. Malfunction of components of a power supply system or electric equipment takes place (see Chapters of the Power supply system and release and engine Electric equipment).
2. Defect in a secondary contour of system of ignition (destruction of insulators of spark plugs or defects of candle wires) takes place (see the Head Elektrooborudovaniye of the engine).
3. The system of injection of fuel needs adjustment or its components are excessively worn-out (see the Head of the Power supply system and release).
4. Losses of depression on the throttle case, the inlet pipeline or through vacuum hoses take place.
5. Valves are jammed (see the Head Dvigatel).
6. The order of connection of candle wires is broken (see the Head Elektrooborudovaniye of the engine).

At the movement with acceleration or uphill there are detonation sounds

1. Low-quality fuel is filled.
2. Malfunction of components of a power supply system or electric equipment takes place (see Chapters of the Power supply system and release and engine Electric equipment).
3. Spark plugs not of that type are established. Check candles and coils for existence of damages (see the Head Elektrooborudovaniye of the engine).
4. Basic installations of the block of electronic control are broken.
5. The detonation sensor is faulty.
6. Depression losses take place.

Kalilny ignition takes place (the engine continues to work after switching off of ignition)

1. Idling turns are excessively high (see the Head Dvigatel).
2. Malfunction of components of a power supply system or electric equipment takes place (see the Head Elektrooborudovaniye of the engine).
3. The valve of a purge of an adsorber of system of catching of vapors of fuel (EVAP) is damaged.
4. Working temperature of the engine is excessive. Decrease in level of cooling liquid (see the Head of the Cooling system, heating), the failure of the thermostat, blocking of a radiator or malfunction of the water pump can be the possible reasons of this violation (see the Head of the Cooling system, heating).

The diesel engine smokes

1. Black smoke:
      a) The air cleaner is polluted, - wash out and fill with fresh oil or replace an element;
      b) Inappropriate fuel is applied, - wash out a tank and replace fuel;
      c) The moment of the beginning of giving of TNVD is incorrectly determined.
2. Blue smoke:
      a) Burning of oil in the combustion chamber owing to wear of piston rings, high level of oil in the air cleaner, wear of epiploons in covers of a turbocompressor, formation of thinnesses in laying between a block case and a turbocompressor, - repair the engine, establish the normal level of oil, replace epiploons, tighten bolts of fastening of a turbocompressor or replace laying;
      b) Fuel to one of nozzles does not move, - check on heating of final branch pipes of a collector;
      c) Bad dispersion of fuel a nozzle because of malfunction of the valve or break of a spray, - grind in the valve or replace a nozzle.
3. White or brown smoke:
      a) Low temperature in the cooling system, - check the thermostat;
      b) Bad work of nozzles owing to wear or break of a spray, - replace a spray.

Engine electric equipment

The battery does not "hold" a charge

1. The driving belt of the generator is worn-out or damaged, or adjustment of its tension is broken (see the Head Elektrooborudovaniye of the engine).
2. Level of electrolyte is insufficient or the battery is strongly discharged (see the Head Elektrooborudovaniye of the engine).
3. Corrosion of plugs of the battery takes place or fastening of tips of wires on them weakened (see the Head Elektrooborudovaniye of the engine).
4. The generator does not provide the required charge current (see the Head Elektrooborudovaniye of the engine).
5. The electrical wiring of a charging contour is torn off or is in any other manner damaged or fastening of wires on plugs weakened (see the Head Elektrooborudovaniye of the engine).
6. Short circuit of an electrical wiring creates continuous leakage of the current developed by the battery on "weight" (address the Head Elektrooborudovaniye of the engine and Schematic diagrams of electric equipment).
7. Internal defect of the battery takes place.

The control lamp of charging does not die away at increase in turns

1. The driving belt is weakened. Check a natyazhitel of a maple belt.
2. Damage of the obgonny coupling (only turbodiesel). Remove the generator and turn a power shaft of the generator to the left. If the working surface of a pulley does not rotate, then damage, as a rule, to the obgonny coupling.
3. Damage of the regulator of the tension/generator. Disconnect a wire (D+) from a reverse side of the generator and include ignition. If now the control lamp does not light up, malfunction, as a rule, in the regulator of tension or in the generator.
4. Wear of brushes. Visually check brushes, if necessary replace.
5. Damage of the regulator. Check, if necessary replace.
6. Damage of the generator. Check, if necessary replace.
7. Damage of a wire between the generator and the regulator of tension.
8. Damage of the block of the dashboard.

The control lamp of charging does not light up at turn of the ignition key in position of ON (at inclusion of ignition)

1. Fused or otherwise the control lamp on the dashboard failed (see the Head Onboard electric equipment).
2. The generator is faulty (see the Head Elektrooborudovaniye of the engine).
3. Defect of the printed circuit board, conducting in the block of the control panel or the boss of a lamp takes place (see the Head Onboard electric equipment).

The control lamp of a charge burns after switching off of ignition

Starter

1. If the starter is not turned, at first it is necessary to check that on the plug of the 50th traction relay there was necessary tension of at least 10 Century. If tension is lower than this value, it is necessary to check according to the scheme of a wire, entering a starter current contour.
2. Whether the starter works at a full tension of the battery, it is possible to check as follows:
      a) Not including transfers, include ignition;
      b) Peremknite starter plugs 30 and 50 a wire of section at least 4 mm2, address also the Section "Check of the Traction Relay" of the Head Elektrooborudovaniye of the engine).
3. If the starter works faultlessly, the cause of defect should be looked for in wires to a starter. If the starter does not earn, it should be checked in the removed state.

Check condition:

In places of connection of a wire have to be well fixed and should not be oxidized.

The starter does not rotate at turning on of the lock of ignition

1. The battery is discharged. Charge the battery.
2. Peremknite starter plugs 30 and 50: The starter rotates. The break of a wire 50 to the ignition lock, is faulty the starter switch. Eliminate break, replace defective parts.
3. Break of a cable or the socket of weight, the battery it is discharged. Check cables and sockets of the battery, measure battery tension, if necessary load.
4. Insufficient passing of current owing to the weakened or oxidized sockets. Clear poles and plugs of the battery, check connections between the battery, a starter and weight.
5. There is no tension on the plug of the 50th traction relay. The break of a wire, the switch of a starter is faulty.

The starter rotates slowly and does not turn the crankshaft

1. Category of the battery. Charge the battery.
2. Summer oil is filled in. Fill in all-weather oil.
3. Insufficient passing of current owing to the weakened or oxidized sockets. Clear poles and plugs of the battery, check connections between the battery, a starter and weight.
4. Coal brushes do not adjoin to a collector, jam in guides, are worn-out, broken, greasy or polluted. Check brushes, clear or replace. Check guides.
5. Insufficient distance between brushes and a collector. Replace brushes and clear guides of brushes.
6. The collector in grooves or burned and was made oily. Process a collector or replace an anchor.
7. There is no tension on the plug 50 (min of 8 V). Check the switch of a starter or the traction relay.
8. The bearing is broken. Check the bearing, if necessary replace.
9. The traction relay is faulty. Replace the traction relay.

The starter grabs and rotates the engine breakthroughs

1. The gear wheel drive is faulty. Replace the gear wheel drive.
2. The gear wheel is polluted. Clear a gear wheel.
3. The gear wreath of a flywheel is faulty. Process a gear wreath if it is required, replace a flywheel.

The gear wheel of a starter does not depart from a wreath

1. The drive of a gear wheel or carving are polluted or damaged. Clear or replace the gear wheel drive.
2. The traction relay is faulty. Replace the traction relay.
3. The returnable spring weakened or became torn. Replace a returnable spring.

The starter continues to work after an ignition key otpuskaniye

1. The traction relay jammed, is not switched-off. At once switch off ignition, replace the traction relay.
2. The ignition lock is not switched-off. At once switch-off the battery, replace the ignition lock.

Power supply system

Fuel consumption is excessive

Petrol models

1. The element of the air filter is polluted or blocked (see the Head of the Power supply system and release).
2. Malfunction of components of a power supply system, electric equipment or electronic control takes place (see Chapters of the Power supply system and release and engine Electric equipment).
3. Leaks in system of an admission of air.
4. Damages of system of release / catalytic converter.
5. Pressure in tires is not enough or tires not of that size are installed.

Diesel engine

1. Contamination of the returnable pipeline. Blow air the returnable pipeline from TNVD to the fuel tank.
2. Too high turns of idling and maximum turns. Adjust.
3. The engine has mechanical damages. Check a compression, if necessary repair the engine.

Leak of fuel takes place and/or there is a gasoline smell

1. There are leaks in lines of supply of fuel or ventilating lines (see the Head of the Power supply system and release).
2. The fuel tank is overflowed. You make gas station only before automatic shutdown of the gun.
3. Take place of leak or evaporation from lines of a power supply system and decrease in toxicity of the fulfilled gases (see the Head of the Power supply system and release).

The engine is not started

1. At inclusion of a starter the electric fuel pump does not work (noise from work is not heard). Slightly knock on a pump housing to release the jammed detail. Check whether tension is put to the pump. Check serviceability of a safety lock. Check electric contacts for good conductivity.
2. The relay of the fuel pump is faulty. Check the relay.
3. The emergency switch of supply of fuel under the driver's seat worked. Drown the switch button.
4. Valves of injectors stuck. Check injectors, if necessary replace. Check giving of tension for injectors. For this purpose to a rasstykuyta socket of injectors. Attach a diode control lamp to a wire and include a starter. The control lamp has to blink.
5. There is no signal from the sensor of ignition of Hall or the sensor of temperature of cooling liquid. Check electric wires. Carry out a survey of memory of malfunctions.
6. Fuel pipelines are damaged, littered or untight, there are defects of hoses.
7. The fuel filter is littered.
8. The inlet system is untight. Additional air Podsasyvatsya.
9. Vacuum pipelines are damaged or untight.
10. Pressure regulator is damaged. Check residual pressure.
11. The sensor of provision of a butterfly valve is damaged.
12. There is no power supply of the block of electronic control by the engine.
13. Availability of ice or wax in the filter or pipelines of the diesel engine.
14. Ventilation of the fuel tank is hammered, the filter in a tank is littered.
15. Preheat does not work.
16. The valve of a cut-off of fuel of the diesel engine is damaged.
17. The moment of the beginning of supply of fuel is brought down.
18. Nozzles of the diesel engine are damaged. Turn off in turn cap nuts and check whether the corresponding cylinder works.
19. TNVD is faulty.

The cold engine is started badly, works unstably

1. Contents WITH does not conform to requirements. Check contents WITH and idling.
2. The sensor of temperature of the cooling liquid / the soaked-up air is faulty. Check the sensor.
3. Pressure of fuel does not correspond to the required value. Check fuel pressure.
4. The inlet system is untight. Additional air Podsasyvatsya.

The warm engine is started badly, works unstably

1. The system of an admission of air is untight. Check inlet system. For this purpose leave the engine to idle and cover places of consolidations and connection on an inlet path with gasoline. If speed for a short time increases, eliminate untight places.

2. The backpressure valve of the fuel pump is damaged.
3. Leaks in fuel system.
4. Elevated pressure of fuel in a power supply system.
5. Malfunction of system of catching of vapors of fuel.
6. The returnable fuel-supply line to a tank is hammered or crumpled.
7. Valves of injectors stuck. Check injectors, if necessary replace. Check giving of tension for injectors. For this purpose to a rasstykuyta socket of injectors. Attach a diode control lamp to a wire and include a starter. The control lamp has to blink.
8. There is no signal from the sensor of ignition of Hall or the sensor of temperature of cooling liquid. Check electric wires. Carry out a survey of memory of malfunctions.
9. The inlet system is untight. Additional air Podsasyvatsya.
10. Vacuum pipelines are damaged or untight.
11. Pressure regulator is damaged. Check residual pressure.
12. The sensor of provision of a butterfly valve is damaged.
13. There is no power supply of the block of electronic control by the engine.

The engine works with interruptions

1. Electric connections to the fuel pump are interrupted from time to time. Check a condition of shtekerny connections and sockets of electric wires of the fuel pump, measuring instrument of a stream of air and the relay of the fuel pump. Check a safety lock and places of contacts for the relay of the fuel pump. Clear contacts, if necessary replace.
2. Poor quality of fuel, formation of steam traffic jams. Fill qualitative fuel.
3. Too low volume of supply of fuel. Check pump productivity.
4. The fuel filter is faulty. Replace the fuel filter.
5. The fuel pump is faulty. Check the fuel pump.
6. Injectors are faulty. Check injectors.
7. It is faulty a lambda probe, violations in a chain of quality management of mix or there is no heating a lambda probe.
8. The sensor of provisions of a butterfly valve is faulty. Check the sensor of provisions of a butterfly valve.
9. The final collector or reception pipe of system of release is damaged (there is leak of exhaust gases).
10. Malfunction of system of catching of vapors of fuel.
11. Fastening of fuel hoses to TNVD and the fuel filter of the diesel engine weakened.
12. At connection the giving and returnable TNVD pipelines are mixed by places.
13. Valves of injectors stuck. Check injectors, if necessary replace. Check giving of tension for injectors. For this purpose to a rasstykuyta socket of injectors. Attach a diode control lamp to a wire and include a starter. The control lamp has to blink.
14. There is no signal from the sensor of ignition of Hall or the sensor of temperature of cooling liquid. Check electric wires. Carry out a survey of memory of malfunctions.
15. The inlet system is untight. Additional air Podsasyvatsya.
16. Vacuum pipelines are damaged or untight.
17. Pressure regulator is damaged. Check residual pressure.
18. The sensor of provision of a butterfly valve is damaged.
19. There is no power supply of the block of electronic control by the engine.

The engine works with interruptions on the transitional modes and in the idling mode

1. The system of an admission of air is untight. Check connections of inlet system. Start the engine and grease with gasoline of the place of contact and connection in the soaking-up highway. If engine turns quickly increase, eliminate leakage.
2. Idling adjustment is incorrect. Check the idling regulator, the sensor of provisions of a butterfly valve, a lambda adjustment.
3. The sensor of full loading is faulty or incorrectly adjusted. Check the sensor of a butterfly valve.

The hot engine is not started

1. Incorrect adjustment of contents WITH. Check contents WITH and idling.
2. Too high pressure in fuel system. Check fuel pressure, if necessary replace pressure regulator.
3. The returnable pipeline between the regulator of pressure and the fuel tank is littered or bent. Clean or replace the pipeline.
4. The engine temperature sensor is faulty. Check temperature sensor.
5. The power supply system is untight. Make visual survey of all connections in the field of the engine and the electric fuel pump. Tighten all connections.
6. The system of an admission of air is untight. Check all connections of inlet system.

The engine works after switching off

1. Injectors are untight. Check injectors.
2. The fuel cut-off valve does not work at the diesel engine.

Lubrication system

The control lamp does not burn after inclusion of ignition

1. The oil pressure sensor is faulty. Include ignition, disconnect a wire from the sensor of pressure of oil and close on "weight". If the lamp lights up, replace the sensor.
2. On the sensor tension, contacts of a korrozirovana does not move. Check electric wires and contacts.
3. The control lamp is faulty. Replace a control lamp.
4. The monitor is faulty. Replace the monitor.

The control lamp does not die away after start of the engine

The control lamp does not die away after supply of gas or lights up during the movement

1. Oil pressure too low. Check oil level, if necessary add. Check oil pressure.
2. The wire to the sensor of pressure of oil has short circuit on "weight". Disconnect a cable from the sensor and take aside (without closing on "weight"), include ignition. If the lamp lights up, check a wire.
3. The sensor of pressure of oil is faulty. Replace the sensor.

Too low pressure of oil on all turns

1. In the engine there is not enough oil. Add oil.
2. The mesh filter is littered. Remove the case pallet, clear the mesh filter.
3. The oil pump is worn-out. Remove the oil pump and check it, if necessary replace.
4. Damages of bearings. Remove the engine.

Too low pressure of oil on small turns

Too high pressure of oil with a frequency of rotation of the engine of 2000 rpm

Cooling system

Overheat

1. Insufficiently cooling liquid in system (see the Head of the Cooling system, heating).
2. The driving belt of the water pump is worn-out or damaged or adjustment of its tension is broken (see Chapters Routine maintenance and the Engine).
3. Internal channels of a radiator are blocked or it is polluted the front grille (is blocked) (see the Head of the Cooling system, heating).
4. The thermostat is faulty (see the Head of the Cooling system, heating).
5. Fan blades are broken or burst (see the Head of the Cooling system, heating).
6. The fan sensor switch is faulty.

   At short circuit of red-yellow and red-white wires of the sensor the fan has to earn from half speed.

7. The index of temperature of cooling liquid is faulty. Check the sensor.
8. The water pump is faulty. Remove and check the pump.
9. Does not hold pressure a radiator cover. Make check of a cover under pressure.

Overcooling

1. The thermostat is faulty (see the Head of the Cooling system, heating).
2. Indications of the measuring instrument of temperature are inexact.

External leak of cooling liquid

1. Hoses are damaged or destroyed as a result of material aging or their fastening on unions weakened. Replace hoses and/or tighten collars of their fastening (see the Head of the Cooling system, heating).
2. Epiploons of the water pump are spoiled. In this case cooling liquid will exude through a control opening in a pump housing (see the Head of the Cooling system, heating).
3. Leaks from internal channels of a radiator or the side tank(s) take place. Repair of a radiator is required.
4. Leaks through a drain stopper of the engine (see the Head Dvigatel) or release traffic jams of water galleries take place (see the Head of the Cooling system, heating).

Internal leak of cooling liquid

1. Leaks through laying of a head of cylinders take place. Make check of the cooling system pressure.
2. There are cracks on walls of cylinders or in casting of a head. For check disassemble the engine (see the Head Dvigatel).

There are losses of cooling liquid

1. In system too much cooling liquid is filled (see the Head of the Cooling system, heating).
2. Cooling liquid boils away as a result of an engine overheat.
3. Internal or external leak of cooling liquid takes place.
4. The radiator cover is faulty. Check a cover pressure.

Circulation of cooling liquid is broken

1. The water pump does not function properly. It is the simplest to make sure of functioning of the pump having pressed the top hose of a radiator at the engine working at single turns. If at an otpuskaniye of a hose the liquid push in it is felt, the pump functions regularly (see the Head of the Cooling system, heating).
2. Passability of the cooling system is broken. Merge cooling liquid, wash out system and fill it with fresh mix (see the Head of the Cooling system, heating). If there is such need, remove a radiator (see the Head of the Cooling system, heating) and carry out its obratnopotochny washing.
3. The driving belt of the water pump is worn-out or damaged or adjustment of its tension is broken (see Chapters Routine maintenance and the Engine).
4. The thermostat is jammed (see the Head of the Cooling system, heating).

Heater

The fan of a heater does not work

1. The fan motor safety lock is faulty. Check a fan safety lock, if necessary replace.
2. the fan switch is faulty. Check whether tension is put to preresistors, remove and check the fan switch.
3. The electric motor is faulty. Check whether tension at the included ignition and the closed fan switch is put to contacts of the motor of the fan. If tension is put, replace the motor.

The fan of a heater does not work at one of steps

The heater is not switched off by the regulator

1. The switch is faulty. Check the switch.
2. Cables of the adjusting mixing gate are damaged or badly mobile. Replace cables.

Too low power of heating

1. Too low level of cooling liquid. Check the level of cooling liquid, if necessary add.
2. The control unit of a heater has the heavy course, is faulty. Check the heater control unit, if necessary replace a cable.

Noise in the field of the heater fan

1. Dirt, leaves got. Remove the fan and clean it, clear the air channel.
2. Disbalance of a krylchatka, malfunction of the bearing. Remove the fan motor, check ease of the course.

Automatic Transmission (AT)

The common problems connected with functioning of the mechanism of switching

1. It is possible to carry the following to number of the refusals connected with violation of adjustment of draft of switching:
      a) Start of the engine is possible at provisions of transmission, excellent from "Р" (Parking) and "N" (Neutral);
      b) Indications of the indicator of provision of transmission differ from really chosen transfer;
      c) The car moves at the transmission established in situation "P" or "N";
      d) Transfers switch hardly or randomly.
2. Make adjustment of draft of gear shifting (see the Head Korobk of gear shifting).

Transmission revolves, switches hardly, publishes extraneous noises or does not provide the movement of the car at installation on one of lobbies or the reverse gear

1. There is a set of the possible reasons of the problems listed in heading, however under competence of the amateur mechanic only one of them - the wrong level of transmission liquid gets.
2. Before driving away the car in a workshop of car service check the level and a condition of transmission liquid (see the Head Routine maintenance). Modify level according to requirements of Specifications) or replace liquid together with the filter. If the situation did not improve, ask for the help experts.

Leak of transmission liquid takes place

1. AT liquid has dark red color. Traces of its leaks should not be confused to traces of motive oil which can be demolished on a transmission case by the running air stream.
2. For identification and localization of a source of leak first of all remove all traces of dirt and lubricant from the transmission boat. Use suitable degreaser and/or make steam cleaning. Then make on the car a short trip at a small speed (that traces of leak did not communicate the running stream far from its source). Stop, the car and by visual survey establish to a poddomkratta a leak source. Most often act as those:
   
      a) The transmission case pallet, - tighten fixing bolts and/or replace laying of the pallet;
      b) A tube of gas station of liquid, - replace rubber consolidation in the place of an entrance of a tube to a transmission case;
      c) Lines of transmission liquid, - tighten nipple connections or replace lines;
      d) The ventilating tube, - transmission is crowded and/or water got to it.

Oil has brown color or smells of ashes

Low level of liquid in a box (see the Head Routine maintenance).

The kickdown mode does not join by full pressing a pedal (the low gear does not join)

1. Low level of liquid in a box (see the Section of the Head Routine maintenance).
2. Malfunction in a control system of the engine (see the Power supply system and injection of fuel of the petrol engine - the general information and System of injection of fuel of the diesel engine - the general information of the Head of the Power supply system and release).
3. Malfunction of the sensor or its conducting (see. Automatic transmission 722.6 Heads Automatic transmission).
4. Adjustment of a cable of the selector is broken (see. Automatic transmission 722.6 Heads Automatic transmission).

The engine is not started at any position of the selector or also "R" is started in any situation except "Р"

1. Adjustment of the sensor of permission of start is broken (see. Automatic transmission 722.6 Heads Automatic transmission).
2. Malfunction in a control system of the engine (see the Power supply system and injection of fuel of the petrol engine - the general information and System of injection of fuel of the diesel engine - the general information of the Head of the Power supply system and release).
3. Adjustment of a cable of the selector is broken (see. Automatic transmission 722.6 Heads Automatic transmission).

Transmission revolves, breakthroughs or noise at gear shifting. The car does not move at inclusion of the D or R modes

1. Low level of liquid in transmission (see the Head Routine maintenance).
2. Malfunction of the sensor or its conducting (see. Automatic transmission 722.6 Heads Automatic transmission).
3. Malfunction in a control system of the engine (see the Power supply system and injection of fuel of the petrol engine - the general information and System of injection of fuel of the diesel engine - the general information of the Head of the Power supply system and release).

Bridges

Extraneous noises

1. Usual road noise. Adjustment is not given in.
2. Noise of tires. Check a condition of protectors and pressure of a rating of tires.
3. Bearings of wheels are worn-out or damaged, or the effort of their tightening weakened.

Vibrations

Oil leak

Brake system

The increased brake pedal course

The pedal of a brake springs and fails

1. Air in the brake system. Remove air from system.
2. There is not enough liquid in the tank. Add new brake fluid, remove air from system.
3. Formation of vials of steam. It is shown, mainly, at big load of brakes. Replace brake fluid, remove air from system.

Decrease in effect of braking, pedal fails

1. Leakage of the pipeline. Delay connections of the pipeline or replace tubes.
2. Damage of cuffs to the main thing or working brake cylinders. Replace a cuff. In the main brake cylinder replace internal elements, if necessary replace the main cylinder.
3. Rubber laying is damaged. Repair a support.

Bad braking despite big effort of pressing of a pedal

1. Brake slips are greasy. Replace brake shoes.
2. The improper or hardened blocks are established. Replace blocks. Establish original blocks of Mercedes-Benz.
3. The brake amplifier is faulty. Check the brake amplifier.
4. Brake shoes are worn-out. Replace brake shoes.

When braking the car takes away aside

1. Pressure in tires does not correspond to demanded. Check and modify pressure in tires.
2. Uneven wear of tires. Replace worn-out tires.
3. Brake shoes are greasy. Replace blocks.
4. On one axis different brake shoes are established. Replace blocks. Establish original blocks of Mercedes-Benz.
5. Bad condition of brake shoes. Replace blocks.
6. Mines of supports are polluted. Clear guides and landing surfaces of blocks in a support.
7. Corrosion of cylinders of brake supports. Replace a support.
8. Uneven wear of a brake shoe. Replace brake shoes (on both wheels).

Spontaneous braking

1. The compensation opening in the main brake cylinder is littered. Clean the main cylinder and replace internal elements.
2. Too small gap between a driving rod and the piston of the main brake cylinder. Check a gap.

Brakes heat up during the movement

1. The compensation opening in the main brake cylinder is littered. Clear the main cylinder and replace internal elements.
2. Too small gap between a driving rod and the piston of the main brake cylinder. Check a gap.
3. The drosseliruyushchy opening in the special valve on the bottom is littered. Clear the main brake cylinder, replace internal elements and brake fluid.

Brakes shiver

1. Blocks of inadequate type are established. Replace blocks, establish original blocks of Mercedes-Benz.
2. Brake disk in places корродирован. Carefully grind a brake disk.
3. The brake disk has a side beating. Process a disk or replace.

Brake shoes do not depart from a brake disk, the wheel is hardly turned manually

Uneven wear of blocks

1. Blocks of inappropriate type are established. Replace blocks, establish original blocks of Mercedes-Benz.
2. The support is polluted. Clear the mine of a support.
3. Heavy piston stroke. Eliminate.
4. The brake system is untight. Check tightness of the brake system.

Wedge-shaped wear of brake shoes

1. The brake disk rotates not parallel to a support. Check support prileganiye surfaces.
2. Corrosion in supports. Eliminate pollution.
3. The piston works incorrectly. Check position of the piston.

Scratch of brakes

1. Often the reason in atmospheric influence (humidity of air). If the scratch appears after the long parking at the increased humidity and then vanishes, it is not necessary to do anything.
2. Blocks of inappropriate type are established. Replace blocks, establish original blocks of Mercedes-Benz, cover basis plates with protivoskripny (antivizgovy) paste.
3. The brake disk rotates not parallel to a support. Check surfaces of a prileganiye of a brake support.
4. The mine of a support is polluted. Clear the mine of a support.
5. Springs of fastening of blocks are bent. Replace fastening springs.
6. Press springs are stretched. Replace press springs.

Brake pedal pulsation

1. ABS in operation. Normally, the help is not required.
2. Too big side beating or the admission on thickness of a brake disk. Check a beating and thickness. Process or replace a disk.
3. The brake disk rotates not parallel to a support. Check a support prileganiye surface.

The control lamp of ABS lights up during the movement

1. Too low voltage of food (it is lower than 10 V). Check tension. Check whether the control lamp of the generator after start of the engine dies away. If everything is all right, check maple a generator drive belt.
2. ABS damage. Check reliability of contact and presence of corrosion of accession of weight at the returnable pump (in the hydraulic block).

Suspension bracket and steering

The car takes away at the movement in one of the parties

1. Tires are pumped unevenly up.
2. Defect of tires takes place.
3. Components of a suspension bracket or steering are excessively worn-out (see the Head Podvesk and steering).
4. Carrying out adjustment of angles of installation of forward wheels is required.
5. Forward brake mechanisms are taken (see the Head the Brake system).

Breakthroughs, pulling or vibrations take place

1. Balancing of wheels is broken or ovality of disks appeared. Make balancing in a tire workshop.
2. Bearings of wheels are worn-out, the effort of their tightening weakened or adjustment is broken (see the Head Podvesk and steering).
3. Racks shock-absorbers or other components of a suspension bracket are worn-out or damaged (see the Head Podvesk and steering).

Excessive rocking car "/zaryvaniye" his nose on turns takes place or when braking

1. Racks shock-absorbers are faulty. Replace all set (see the Head Podvesk and steering).
2. Suspension bracket components are damaged. Make check of a condition of components (see the Head Podvesk and steering).

Too hardly the steering wheel rotates

1. Excessively liquid level fell in the tank of system of hydrostrengthening of a wheel (see the Head Podvesk and steering).
2. Tires are pumped incorrectly up.
3. Hinges of the steering drive are insufficiently greased (see the Head Podvesk and steering).
4. Adjustment of angles of installation of forward wheels is broken.
5. The hydraulic booster does not develop the required power.

The excessive side play of steering takes place

1. The effort of tightening of bearings of forward wheels weakened (see the Head Podvesk and steering).
2. Components of a suspension bracket or steering are excessively worn-out (see the Head Podvesk and steering).

The system of hydrostrengthening of a wheel does not develop due effort

1. The driving belt of the pump of the hydraulic booster is worn-out or damaged or adjustment of his tension is broken (see the Head Podvesk and steering).
2. Excessively liquid level fell (see the Head Podvesk and steering).
3. Passability of hoses or lines of hydraulic system is broken. Check, in case of need make replacements.
4. Air got to hydraulic system. Pump over system (see the Head Podvesk and steering).

Excessive wear of protectors takes place (not in one some area)

1. Tires are pumped incorrectly up.
2. Balancing of wheels is broken. Address in a tire workshop.
3. Disks of wheels are damaged. Check, in case of need make replacement.
4. Components of a suspension bracket or steering are excessively worn-out (see the Head Podvesk and steering).

Excessive wear of protectors on an outer edge takes place

1. Tires are pumped incorrectly up.
2. Turns are too sharply made. Reduce speed.
3. Adjustment of angles of installation of forward wheels (excessive convergence) is broken. Address in a workshop for carrying out professional adjustment.
4. The suspension bracket lever is bent or twisted (see the Head Podvesk and steering).

Excessive wear of protectors on an inner edge takes place

1. Tires are pumped incorrectly up.
2. Adjustment of angles of installation of forward wheels is broken (divergence). Make adjustment in a workshop of car service.
3. Components of steering are damaged or their fastening weakened (see the Head Podvesk and steering).

Local wear of a protector takes place

1. Balancing of wheels is broken.
2. Disks are damaged or bent. Check, in case of need make replacement.
3. Defect of tires takes place.

Defects of brushes of a screen wiper

Slipping

1. Elastic bands are polluted. Clear elastic bands a rigid nylon brush and solution of detergent or alcohol.
2. Shabby edges of brushes, elastic bands are worn-out or broken off. Replace elastic bands.
3. Old elastic bands, the cracked surfaces. Replace elastic bands.

In the field of cleaning the water remains gather in drops at once

The brush clears unilaterally - in one party well, in another is not present

1. The elastic band is deformed in one party "does not overturn any more". Establish a new elastic band.
2. The lever of a screen wiper is twisted, the brush not precisely adjoins to glass. Carefully turn the lever, vertical position will not be reached yet.

Crude surfaces

1. The elastic band escaped from a frame. Carefully insert an elastic band into a frame.
2. The brush adjoins to glass unevenly as spring levels or plates are bent. Replace a brush. This malfunction first of all appears at negligent installation of a spare brush.
3. Pressing force the lever is too small. Slightly grease hinges of levers of a screen wiper and spring or install the new lever.

Defects of tires

Strong wear of the tire on both parties of a working surface

Strong wear of the tire in the middle of a working surface on all circle of a protector

Uneven wear of a protector

Uneven wear in the middle of a protector

Strong wear of certain sites in the middle of a working surface of a protector

Sawtooth wear of a protector, it is frequent together with a rupture of a fabric basis of the tire invisible outside

Rubber uvulas on side edges of a protector (scaly wear)

Formation of agnails on one party of a protector of a forward wheel

Ruptures of a cord. At first are visible only from within

Unilateral wear of a working surface of a protector

1. Check adjustment of disorder.
2. ABS damage. Check reliability of contact of connection with the case at the returnable pump (in the hydraulics block).