Audi A4 B6 - the Repair manual and operation

1.9. 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 as, for example the engine, the cooling system, etc., besides, in the text are given the references concerning these problems.

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. That the petrol engine in general could be started, two main conditions have to be satisfied. Fuel-air mix has to come to cylinders, and on a spark plug the spark has to be developed. Therefore, first, it is necessary to check whether fuel moves. Address the Head of the Power supply system, release and decrease in toxicity 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 you do not hold a tip or a cable of ignition with hands, and use well isolated nippers. Ask the assistant to start the engine. If the spark is absent, address the Head Sistemy of electric equipment of the engine.

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

Start of the engine

All engines

- manual transmission: Tighten the parking brake, completely squeeze out a pedal of coupling and you hold it. Establish the check point in neutral situation. The switched-off coupling facilitates start of the engine, especially at low external temperatures since at the same time there is no friction from the check point.

- Automatic transmission: Install the selector in situation "P" or "N". Press a pedal of a brake and you hold it.

Do not include a starter more than 30 with continuously, otherwise the starter and cables overheat.

Petrol engine

• Turn the ignition key and include a starter, without giving at the same time gas. As soon as the engine starts working, release a key. If during 5 about the engine it is not started, press the accelerator pedal a little and again repeat start. If the engine is not started or at once stops, repeat start with half the squeezed-out accelerator pedal and if still start with completely squeezed out accelerator pedal is required. At the hot engine during start slowly squeeze out the accelerator pedal.
• Surely at once begin the movement, only at a hard frost let's the engine get warm during 30 pages.
  
  

  The unsuccessful, following one after another attempts of start of the engine can do harm to the catalytic converter since not burned down gasoline gets to it and when heating blows up.

Diesel engine

- On the cold engine: Include ignition and wait when the control lamp of preheat goes out. At once after the control lamp went out, start the engine, without giving at the same time gas. If at start there are irregular flashes, include a starter until then (at most 20 c) until the engine begins to work independently. If after all the engine is not started, turn the ignition key in situation "0" and wait for about 30 pages. After that once again warm up the engine and repeat start as it is described above.

While preheat is made, it is not necessary to include powerful electric consumers, otherwise the rechargeable battery without need is overloaded.

The diesel engine with direct injection, as a rule, demands use of preheat only at a temperature below 0 °C.

If the fuel tank was completely emptied, then process of start after gas station lasts longer (up to 1 min.) since at the same time air from fuel system is removed.

- On the warm engine preheat is not required. Start the engine at once, without giving gas.

The engine is not turned in start attempts

• 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.
• 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 headlights and/or screenwashes. If this electric equipment does not function, the battery is discharged.
• Transmission it is inexact it is established in situation "P".
• Conducting in a chain of system of start is torn off or fastening of wires on plugs weakened. Check a condition of wires, plugs and electric sockets of the battery, traction relay of a starter and the lock of ignition.
• 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.
• The traction relay of a starter (The head Sistemy of electric equipment of the engine) is faulty.
• The starter (The head Sistemy of electric equipment of the engine) is faulty.
• The ignition lock is faulty.

The engine is turned, but not started

• Start is incorrectly made (Address the materials given above).
• The engine immobilizator is faulty or is not disconnected.
• The safety lock is faulty:
  • Electric fuel pump;
  • Electronic system of injection.
• Concerning check of safety locks address the Head Onboard electric equipment.
• The empty fuel tank or low-quality fuel is filled in.
• 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.
• The battery is discharged (the engine is turned too slowly). Check functioning of electric equipment (address the previous Section).
• Korrodirovana terminal connections of the battery or their fastening weakened (address the previous Section).
• The fuel pump is faulty, its safety lock fused or the pump relay is damaged. Check for hearing noise of operation of the pump at inclusion of ignition (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases).
• Components of system of ignition (The head Sistemy of electric equipment of the engine) are damaged or excessively moistened.
• Spark plugs are worn-out or faulty or the candle gap (The head Sistemy of electric equipment of the engine) is incorrectly exposed.
• Conducting of an electric contour of system of start is torn off or disconnected or fastening of wires on plugs weakened (address the previous Section).
• Conducting of a contour of the coil of ignition is torn off or disconnected or fastening of wires on coil plugs (The head Sistemy of electric equipment of the engine) weakened.
• 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 or the soaked-up air (The head Sistemy of electric equipment of the engine).
• Too low pressure of a compression. Replace sealing laying of a head of cylinders. If necessary repair the engine.

Diesel engine

• Start is incorrectly made.
• The engine immobilizator is faulty.
• The safety lock is faulty:
  • Electric fuel pump;
  • Systems of preheat.
• The engine is not heated-up: proverteispravnost of functioning of the device of preheat.
• 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.
• The electromagnetic locking valve is faulty. Check reliability of fastening of the electromagnetic switch, check contacts. Switch on and off ignition. In the switch the click has to sound.
• Damage to the line of supply of fuel or air to lines takes place:
  • Pipelines or hoses are mechanically damaged or littered. Clear fuel pipelines and remove air from lines and the filter.
  • The fuel filter is littered. Replace the filtering element.
  • It is necessary to check the filter and pipelines for availability of ice or wax in the winter. Put the car in the heated garage, add to system of gasoline.
  • Ventilation of a tank or the mesh filter of a toplivozabornik is littered. Clean.
• Adjustment of the beginning of supply of fuel is brought down. Check, make adjustment.
• 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.
• The fuel pump of high pressure (FPHP) is faulty. Establish new, or obviously serviceable TNVD for check.
• Too low pressure of a compression. Replace sealing laying of a head of cylinders. If necessary repair the engine.

The starter functions without engine provorachivaniye

• The starter gear wheel is jammed. Remove a starter (The head Sistemy of electric equipment of the engine) and check its state.
• Teeth of a gear wheel of a starter or wreath of a flywheel are worn-out or damaged.

Start of the cold engine is complicated

• The battery is discharged or insufficiently charged.
• Malfunction a component of a power supply system or electric equipment (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases and System of electric equipment of the engine) takes place.
• Paraffin in the filter of thin cleaning of the diesel engine. Replace a filter element. Fill winter fuel, or dilute with low-octane gasoline.
• Glow plugs of the diesel engine are faulty

Start of the hot engine is complicated

• The air filter (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases) is blocked.
• Malfunction a component of a power supply system or electric equipment (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases and System of electric equipment of the engine) takes place.
• Fuel does not reach injectors of system of injection (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases).
• The corner of an advancing of supply of fuel of the diesel engine got off.
• Low compression in cylinders, TNVD of the diesel engine is faulty or disadjusted.

Gearing of a starter happens is too noisy or with difficulty

• Teeth of a gear wheel of a starter or wreath of a flywheel are worn-out or damaged.
• Bolts of fastening of a starter are lost or the effort of their tightening weakened.

The engine is started, but immediately becomes deaf

• The engine immobilizator is faulty.
• The electrical wiring is faulty or fastening of wires on plugs of the coil or the generator weakened.
• Malfunction a component of a power supply system or electric equipment (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases and System of electric equipment of the engine) takes place.
• Basic installations of the block of electronic control (ESM) are broken.
• Damage to system of release / catalytic converter.
• Losses of depression through the pro-masonry surfaces of the inlet pipeline or block of injection of fuel 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. Check a condition of hoses and correctness of their connection (to the unions).

Stability of operation of the engine on single turns is broken

• Leaks in the inlet air highway 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.
• Malfunction a component of a power supply system or electric equipment (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases and System of electric equipment of the engine) takes place.
  • Serviceability of activation of an injector and control of duration of injection is broken.
  • Leaks through injectors/violation of a stream of dispersion of fuel at injection take place.
  • It is faulty dokataliticheskiya a lambda probe 1.
  • Low voltage of ignition.
• The valve of system of the operated ventilation of a case is blocked (Head Dvigatel).
• It is jammed, or the EGR valve allows leaks.
• The air filter (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases) is blocked.
• The fuel pump does not provide giving of enough fuel to injectors of system of injection (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases).
• Leaks through laying of a head of cylinders take place. Perform measurement of compression pressure in engine cylinders.
• Camshaft cams are worn-out (Head Dvigatel).

Diesel engine

• 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.
• Fastening of TNVD is mechanically damaged or weakened. Check fastening.
• 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".
• Damage to the line of supply of fuel takes place:
  • Pipelines or hoses are mechanically damaged or littered. Clear fuel pipelines.
  • The fuel filter is littered. Replace the filtering element.
  • It is necessary to check the filter and pipelines for availability of ice or wax in the winter. Put the car in the heated garage, add to system of gasoline.
  • Ventilation of a tank or the mesh filter of a toplivozabornik is littered. Clean.
• Adjustment of the beginning of supply of fuel is brought down. Check, make adjustment.
• 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.
• The fuel pump of high pressure (FPHP) is faulty. Establish new, or obviously serviceable TNVD for check.

Admissions of ignition take place during the operation of the engine on single turns

• Spark plugs are worn-out or polluted or the candle gap (The head Sistemy of electric equipment of the engine) is incorrectly exposed.
• Malfunction a component of a power supply system or electric equipment (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases and System of electric equipment of the engine) takes place.
  • Low voltage of ignition; the measuring instrument of mass of MAF air is faulty.
• Wires of spark plugs (The head Sistemy of electric equipment of the engine) are faulty.
• Low-quality fuel is filled. The fuel filter is hammered.
• Losses of depression in the inlet pipeline or through hose connections take place.
• Insufficient, or unequal compression pressure in cylinders. Perform measurement of a compression (Head Dvigatel).
• Violations in work of a control system of the engine take place.

Admissions of ignition at the movement of the car on transfer take place

• The fuel filter is blocked or pollution of a power supply system (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases) takes place.
• Spark plugs are faulty or polluted or the candle gap (The head Sistemy of electric equipment of the engine) is incorrectly exposed.
• Malfunction a component of a power supply system or electric equipment (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases and System of electric equipment of the engine) takes place.
• Defect of candle wires (The head Sistemy of electric equipment of the engine) takes place.
• Components of systems of decrease in toxicity of the fulfilled gases are faulty.
• There is not enough or neravnomernoraspredeleno between cylinders compression pressure. Remove spark plugs and perform measurement of compression pressure (Head Dvigatel).
• The system of ignition (The head Sistemy of electric equipment of the engine) is faulty.
• Losses of depression on the throttle case, the inlet pipeline or through vacuum hoses take place.

The engine becomes deaf

• Adjustment of turns of idling is broken.
• The fuel filter is blocked and/or moisture or dirt (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases) got to a power supply system.
• The refusal a component of a power supply system or sensors (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases) takes place.
• Components of systems of decrease in toxicity of the fulfilled gases are faulty.
• Spark plugs are faulty or polluted or the candle gap is incorrectly exposed (The head the Current leaving and service). Also check a condition of candle wires (The head Sistemy of electric equipment of the engine).
• Losses of depression on the case of a throttle or through vacuum hoses take place.

The engine does not develop full capacity

• Malfunction a component of a power supply system or electric equipment (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases and System of electric equipment of the engine) takes place.
  • It is faulty dokataliticheskiya a lambda probe 1.
  • The sensor of temperature of cooling liquid (ECT) is faulty.
  • The measuring instrument of mass of air (MAF) is faulty.
  • Serviceability of functioning of system of resonant management of pressure pulsations in the inlet pipeline is broken; serviceability of functioning of the control system of a detonation is broken.
• The air cleaner is littered. Clear or replace.
• Spark plugs are faulty or the candle gap is incorrectly exposed (The head the Current leaving and service).
• The ignition coil (The head Sistemy of electric equipment of the engine) is faulty.
• AT liquid level does not conform to requirements (The head the Current leaving and service and Automatic transmission).
• Coupling revolves (The head Stsepleniye, power shafts and differential).
• The fuel filter is blocked and/or dirt/moisture (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases) got to a power supply system.
• Fuel not of that grade is filled. Fill in in a tank fuel with the required octane number.
• The adjusting valve of a turbocompressor is damaged.
• The activator of a cam-shaft of shift of phases GRM is faulty.
• Passability of the three-functional catalytic converter is broken.
• 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 (Head Dvigatel).

In addition for the diesel engine

• The air cleaner is littered. Clean or replace.
• Uneven supply of TNVD fuel on cylinders. Adjust on the heated-up engine.
• The moment of the beginning of supply of TNVD fuel is incorrectly determined. Establish.
• 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).
• 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

• Malfunction a component of a power supply system or electric equipment (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases and System of electric equipment of the engine) takes place.
• Defect in a secondary contour of system of ignition (destruction of insulators of spark plugs or defects of candle wires) (The head Sistemy of electric equipment of the engine) takes place.
• The system of injection of fuel needs adjustment or its components are excessively worn-out (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases).
• Losses of depression on the throttle case, the inlet pipeline or through vacuum hoses take place.
• Valves (Head Dvigatel) are jammed.
• The order of connection of candle wires (The head Sistemy of electric equipment of the engine) is broken.

At the movement with acceleration or uphill there are detonation sounds

• Low-quality fuel is filled.
• Malfunction a component of a power supply system or electric equipment (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases and System of electric equipment of the engine) takes place.
• Spark plugs not of that type are established. Check candles and a katushkin existence of damages (The head Sistemy of electric equipment of the engine).
• Basic installations of the block of electronic control are broken.
• The detonation sensor is faulty.
• Depression losses take place.

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

• Idling turns are excessively high (Head Dvigatel).
• Malfunction a component of a power supply system or electric equipment (The head of the Power supply system, release and decrease in toxicity of the fulfilled gases and System of electric equipment of the engine) takes place.
• The valve of a purge of an adsorber of system of catching of vapors of fuel (EVAP) is damaged.
• Working temperature of the engine is excessive. Decrease in level of cooling liquid (The head of the Cooling system, heating and the air conditioner), failure of the thermostat, blocking of a radiator or malfunction of the water pump (The head of the Cooling system, heating and the air conditioner) can be the possible reasons of this violation.

The diesel engine smokes

• Black smoke:
  • The air cleaner is polluted. Wash out and fill with fresh oil or replace an element.
  • Inappropriate fuel is applied. Wash out a tank and replace fuel.
  • The moment of the beginning of giving of TNVD is incorrectly determined.
• Blue smoke:
  • Burning of oil in the combustion chamber owing to wear of piston rings, high level of oil in the air clea