Mercedes M-Class W163

since 1997 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 Sistemy of electric equipment 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.

Engine

If the engine is not started, it is necessary to analyse a situation. Indispensable conditions of start of any petrol engine are serviceability of giving in cylinders of air-fuel mix and adequacy of sparking on spark plugs.

First of all it is necessary to make sure of serviceability of supply of fuel (see the Head of the Power supply system and production of the fulfilled gases).

To define whether the spark is developed, it is necessary to turn out candles, to insert into tips and to put separately to weight. At the same time it is not necessary to hold a wire or a tip hands, - use the isolated flat-nose pliers. Ask the assistant to start the engine. If the spark is absent, try to define a cause of failure (see the Head Sistemy of electric equipment of the engine).

Procedures of diagnostics of an electronic control system and codes of malfunctions are also provided in the Head Sistemy of electric equipment of the engine.

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.
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.
5. The gear wheel of a starter is jammed in a gear wreath of a driving disk.
6. The traction relay of a starter is faulty.
7. The starter is faulty.
8. The ignition switch is faulty.

The engine is turned, but not started

Petrol models

1. Start is incorrectly made. Act as follows:

1. Cock the parking brake;
2. Include neutral transfer (RKPP) / transfer the selector lever to situation "P" or "N" (AT);
3. Without squeezing out the accelerator pedal, turn a key in the ignition lock to the right against the stop. As soon as the engine is started, at once release a key. If start of the heated-up engine is not possible to make at a provorachivaniye it a starter more than 4 seconds, it is necessary to squeeze out the accelerator pedal slowly. Do not turn the engine more than 30 seconds in a row, before repeated attempt wait not less than 15 seconds;
4. At unstable turns (for example, at admissions of ignition) in order to avoid failure of the catalytic converter try to turn on the engine only for a short time and do not allow strong loadings, - immediately drive away the car on HUNDRED companies Mercedes-Benz;
5. In areas where temperature of external air often falls below -20 °C, installation of a heater of cooling liquid is recommended, - the reference on this matter can be received on any HUNDRED Mercedes-Benzs.

2. The engine immobilizator is faulty or is not disconnected.
3. The safety lock of the electric fuel pump or electronic system of injection is faulty (see the Head Onboard electric equipment).
4. The fuel tank is empty, or is fuelled by low-quality.
5. The air filter is strongly polluted. Leak of vacuum in elements of air supply, malfunction in a control system of injection of fuel and ignition takes place.
6. The battery is discharged (the engine is turned too slowly).
7. Terminal connections of the battery are oxidized, or their fastening weakened.
8. The fuel pump is faulty, or its relay is damaged, - aurally check serviceability of activation of the pump at inclusion of ignition.
9. Components of system of ignition are damaged or excessively moistened.
10. Spark plugs are worn-out or faulty, or the candle gap is incorrectly exposed.
11. The electrical wiring of system of start is torn off or disconnected, or fastening of wires on plugs weakened.
12. The ignition coil electrical wiring is torn off or disconnected, or or fastening of wires on coil plugs weakened.
13. The safety lock of the control unit of the engine is damaged, it is faulty any of sensors: The hall, the pulse sensor, the sensor of temperature of cooling liquid (ECT) or the soaked-up air (IAT).
14. Compression pressure is not enough.

Diesel models

1. Start is incorrectly made. Act as follows:

1. Cock the parking brake;
2. Include neutral transfer (RKPP) / transfer the selector lever to situation "P" or "N" (AT);
3. Turn a key in the ignition lock in situation 2, - on an instrument guard the control lamp of preheat has to light up (see appropriate section of the Head Governing bodies and methods of safe operation). Start of the engine should be carried out not earlier than the control lamp goes out, - without including onboard consumers of the electric power and without squeezing out the accelerator pedal, turn a key in the lock to the right against the stop. At a temperature of external air below -10 °C it is also necessary to squeeze out against the stop the accelerator pedal. Continue to turn the engine a starter until its turns are not stabilized, however no more than 30 seconds. Before restart after unsuccessful attempt do not forget to return at first a key to situation 0 and to wait not less than 15 seconds;
4. You monitor the index of pressure of motive oil (see appropriate section in the Head Governing bodies and methods of safe operation): the indicator of pressure has to be activated at once after start. At strong cooling of the engine indication of pressure appears after start only after a while. Do not increase engine speed, yet not indication of pressure of oil is not activated;
5. If the control lamp of preheat does not light up, then malfunction in system of preheat which has to be immediately eliminated on HUNDRED Mercedes-Benzs takes place;
6. In areas where temperature of external air often falls below -20 °C, installation of a heater of cooling liquid is recommended. On this matter you can receive the reference on any HUNDRED Mercedes-Benzs.

2. The engine immobilizator is faulty
3. The safety lock of the electric fuel pump or system of preheat is faulty.
4. The engine is not heated-up: check serviceability of functioning of the device of preheat.
5. On the electromagnetic locking valve there is no tension. Connect to the switch the voltmeter or a sampler on a light-emitting diode. Include ignition, the light-emitting diode has to light up, otherwise it is necessary to find break of an electrical wiring and to eliminate it.
6. The electromagnetic locking valve is faulty. Check reliability of fastening of the electromagnetic switch, estimate a condition of contacts. Switch on and off ignition, - in the switch the click has to sound.
7. Damage to the line of supply of fuel or air to lines takes place:

1. Pipelines or hoses are mechanically damaged or littered, - clear fuel pipelines and remove air from lines and the filter;
2. The fuel filter is littered, - replace the filtering element;
3. 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;
4. Ventilation of a tank or the mesh filter of a toplivozabornik is littered, - clean.

8. Adjustment of the moment of the beginning of supply of fuel is brought down.
9. Nozzles are faulty, - at an otpuskaniye of a nipple nut of a fuel-supply line of a faulty nozzle turns of the engine will not fall.
10. The fuel pump of high pressure (FPHP) is faulty.
11. Too low pressure of a compression.

The starter functions without engine provorachivaniye

1. The starter gear wheel is jammed.
2. Teeths of a gear wheel of a starter or wreath of a flywheel are worn-out or damaged.

Start of the cold engine is complicated

1. It is discharged, or the battery is insufficiently charged.
2. Violation of serviceability of functioning of components of a power supply system, or electric equipment takes place.
3. In the filter of thin cleaning of the diesel engine settled paraffin.
4. Glow plugs of the diesel engine are faulty.

Start of the hot engine is complicated

1. Passability of the air filter is broken.
2. Violation of serviceability of functioning of components of a power supply system, or electric equipment takes place.
3. Fuel does not arrive to injectors of system of injection.
4. The corner of an advancing of supply of fuel of the diesel engine got off.
5. Compression pressure in cylinders is not enough, TNVD of the diesel engine is faulty, or its adjustment is broken.

Gearing of a starter happens is too noisy or with difficulty

1. Teeths of a gear wheel of a starter or wreath of a flywheel are worn-out or damaged.
2. Bolts of fastening of a starter are lost, or the effort of their tightening weakened.

The engine is started, but at once becomes deaf

1. The engine immobilizator is faulty.
2. The electrical wiring is faulty, or fastening of wires on plugs of the coil or the generator weakened.
3. Violation of serviceability of functioning of components of a power supply system or electric equipment takes place.
4. Basic installations of the module of management of the engine (ESM) are broken.
5. Damage to system of release / the catalytic converter has places.
6. Losses of depression through the pro-masonry surfaces of the inlet pipeline or block of injection of fuel take place.

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. Violation of serviceability of functioning of components of a power supply system or electric equipment takes place.
3. Passability of the valve of system of the operated ventilation of a case is broken.
4. Passability of the air filter is broken.
5. The fuel pump does not provide giving of enough fuel to injectors of system of injection.
6. Leaks through laying of a head of cylinders take place, - perform measurement of compression pressure in engine cylinders (see the Head Dvigatel).
7. Working ledges of cams of the camshaft are worn-out.

Diesel models

1. Quality of connections of fuel hoses on TNVD and the fuel filter is broken.
2. Fastening of TNVD is mechanically damaged or weakened.
3. Are mixed by junctions of the returnable pipeline and pipeline of supply of fuel.
4. Damage to the line of supply of fuel takes place:

1. Pipelines or hoses are mechanically damaged or littered, - clear fuel pipelines;
2. The fuel filter is littered. Replace the filtering element;
3. 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;
4. 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.
6. Nozzles are faulty, - at an otpuskaniye of a nipple nut of a fuel-supply line of a faulty nozzle 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.
2. Malfunction of components of a power supply system or electric equipment takes place.
3. VV an electrical wiring is faulty.
4. Low-quality fuel is filled, or passability of the fuel filter is broken.
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.
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.
2. Spark plugs are faulty or polluted or the candle gap is incorrectly exposed.
3. Malfunction of components of a power supply system or electric equipment takes place.
4. Defect of VV of an electrical wiring takes place.
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.
7. The system of ignition is faulty.
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. Passability of the fuel filter is broken, or moisture or dirt got to a power supply system.
3. The refusal of components / information sensors of a power supply system takes place.
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 of the Power supply system and production of the fulfilled gases). Also check a condition of VV of an electrical wiring.
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.
2. The air cleaner is littered.
3. Spark plugs are faulty or the candle gap is incorrectly exposed.
4. The ignition coil is faulty.
5. AT liquid level fell (see the Head of the Power supply system and production of the fulfilled gases).
6. Transmission revolves.
7. The fuel filter is blocked and/or dirt/moisture got to a power supply system.
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 at the corresponding complete set).
10. The activator of the camshaft of shift of phases GRM is faulty.
11. Insufficiently compression pressure, or uniformity of its distribution between cylinders is broken.

In addition for the diesel engine

1. The air cleaner is littered.
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.
4. The fuel filter or TNVD (nozzle) is littered.
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. Violation of serviceability of functioning of components of a power supply system or electric equipment takes place.
2. Defect in a secondary contour of system of ignition (destruction of insulators of spark plugs or damage of VV of an electrical wiring) takes place.
3. The system of injection of fuel needs adjustment, or its components are excessively worn-out.
4. Losses of depression on the throttle case, the inlet pipeline or through vacuum hoses take place.
5. Valves are jammed.
6. The order of connection of VV of an electrical wiring is broken.

At the movement with acceleration or uphill there are detonation sounds

1. Low-quality fuel is filled.
2. Violation of serviceability of functioning of components of a power supply system or electric equipment takes place.
3. Spark plugs not of that type are established.
4. The basic ECM installations 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.
2. Malfunction of components of a power supply system or electric equipment takes place.
3. Serviceability of functioning of the valve of a purge of an adsorber of system of catching of vapors of fuel (EVAP) is broken.
4. Working temperature of the engine is excessive. Decrease in level of cooling liquid, failure of the thermostat, blocking of a radiator or malfunction of the water pump can be the possible reasons of this violation.

The exhaust of the diesel engine excessively smoke-filled

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 Sistemy of electric equipment of the engine).
2. Level of electrolyte is insufficient or the battery is strongly discharged.
3. Corrosion of plugs of the battery takes place or fastening of tips of wires on them weakened.
4. The generator does not provide the required charge current.
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.
6. Short circuit of an electrical wiring creates continuous leakage of the current developed by the battery on "weight".
7. Internal defect of the battery takes place.

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

1. The driving belt is weakened.
2. The obgonny coupling of the hydrotransformer is damaged (only a 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. The regulator the tension/generator is damaged. Disconnect a wire (D+) from a reverse side of the generator and include ignition. Further it is necessary to check a condition of the regulator of tension of the generator.
4. Brushes are worn-out.
5. The wire between the generator and the regulator of tension is damaged.
6. The combination of devices is faulty.

The control lamp of a charge does not light up at inclusion of ignition

1. Fused or otherwise the control lamp on the dashboard failed.
2. The generator is faulty.
3. Defect of the printed circuit board, conducting in the block of a combination of devices or the boss of a lamp takes place.

The control lamp of a charge does not die away after switching off of ignition

1. Diodes are punched.

Starter

If the starter is not turned, at first it is necessary to check that at the plug No. 50 of the traction relay there was necessary tension (at least 10 V). At negative results of check it is necessary to estimate a starter current contour electrical wiring condition.

For check of serviceability of operation of a starter at a full tension of the battery perform the following operations:

a) Not including transfers, include ignition;
b) Peremknite starter plugs 30 and 50 wire with a section not less than 4 mm ².

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.

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

1. The battery is discharged.
2. Peremknite starter plugs 30 and 50: if the starter rotates, check for break a wire 50 to the ignition lock, estimate also a condition the starter switch.
3. The weight wire is torn off, or quality of its terminal connection is broken, the battery is discharged.
4. Weakening of current owing to violation of quality or oxidation of contact connections.
5. There is no tension on the plug of the 50th traction relay as a result of break of an electrical wiring, or damage of the switch of a starter.

The starter rotates slowly and does not turn a bent shaft

1. The battery is discharged.
2. Summer oil is filled in.
3. Insufficient passing of current owing to the weakened or oxidized sockets.
4. Coal brushes do not adjoin to a collector, jam in guides, are worn-out, broken, greasy or polluted.
5. Insufficient distance between brushes and a collector.
6. The collector in grooves or burned and was made oily.
7. There is no tension on the plug 50 (at least 8 V).
8. The bearing is broken.
9. The traction relay is faulty.

The starter grabs and rotates the engine breakthroughs

1. The gear wheel drive is faulty.
2. The gear wheel is polluted.
3. The gear wreath of a flywheel is faulty.

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

1. Gear wheel drive components are polluted or damaged.
2. The traction relay is faulty.
3. The returnable spring weakened or became torn

The starter continues to work after an ignition key otpuskaniye

1. The traction relay is jammed, - immediately switch off ignition and replace the traction relay.
2. The ignition lock is not switched-off, - 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.
2. Malfunction of components of a power supply system, electric equipment or electronic control takes place.
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. Turns of idling and the maximum turns are excessively high.
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. Leaks in lines of supply of fuel or ventilating lines take place.
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 power supply systems and decrease in toxicity of the fulfilled gases.

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 serviceability of giving to the pump tension (check serviceability of a protective safety lock and reliability of fastening of contact plugs of the corresponding electrical wiring).
2. The relay of the fuel pump is faulty.
3. Valves of injectors stuck. Check injectors, if necessary replace. Check giving of tension for injectors, - disunite the contact socket of an injector, and connect a diode lamp sampler to a wire and include a starter: the lamp has to begin to blink.
4. There is no signal from the sensor of ignition of Hall or the sensor of temperature of cooling liquid. Check a condition of the corresponding electrical wiring, carry out a survey of memory of system of onboard self-diagnostics.
5. Fuel pipelines are damaged, littered or untight, there are defects of hoses.
6. The fuel filter is littered.
7. To the inlet highway as a result of violation of tightness excess air podsasyvatsya.
8. Vacuum pipelines are damaged or untight
9. Pressure regulator is damaged, - check residual pressure.
10. The sensor of provision of a butterfly valve is damaged.
11. There is no power supply of the block of electronic control by the engine.
12. Availability of ice or wax in the filter or pipelines of the diesel engine.
13. Ventilation of the fuel tank is hammered, the filter in a tank is littered.
14. Preheat does not work.
15. The valve of a cut-off of fuel of the diesel engine is damaged.
16. The moment of the beginning of supply of fuel is brought down.
17. Nozzles are faulty, - at an otpuskaniye of a nipple nut of a fuel-supply line of a faulty nozzle turns of the engine will not fall.
18. TNVD is faulty.

The cold engine is started badly, works unstably

1. Contents WITH does not conform to standard requirements, - perform the corresponding measurement, check idling turns.
2. The sensor of temperature of cooling liquid (ECT) or the soaked-up air (IAT) is faulty.
3. Pressure of fuel does not correspond to the required value.
4. To the inlet highway as a result of violation of tightness excess air podsasyvatsya.

The warm engine is badly started, 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, - disunite the contact socket of an injector, and connect a diode lamp sampler to a wire and include a starter: the lamp has to begin to blink.
8. There is no signal from the sensor of ignition of Hall or the sensor of temperature of cooling liquid. Check a condition of the corresponding electrical wiring, carry out a survey of system of onboard self-diagnostics.
9. To the inlet highway as a result of violation of tightness excess air podsasyvatsya. </