Audi A4, S4

since 2000 release

Repair and operation of the car



Audi A4, S4
+ Introduction
+ Governing bodies and methods of safe operation
+ Current leaving and service
+ Engine
+ Cooling systems, heating and air conditioner
+ Power supply systems, release and decrease in toxicity of the fulfilled gases
+ Systems of electric equipment of the engine
+ Manual box of gear shifting
+ Automatic transmission
+ Coupling, power shafts and differential
+ Brake system
+ Suspension bracket and steering
+ Body
- Onboard electric equipment
   Specifications
   Diagnostics of malfunctions of onboard electric equipment - the general information
   Rassoyedineniye of sockets
   Check of the electric motor of a screen wiper
   Check of the warmed back glass
   Check of stoplights
   Removal and installation of a sound signal
   Removal and installation of sensors of a parking
   Replacement of the battery of a remote control of the ignition key
   Relay and safety locks
   Replacement of glow lamps of devices of external lighting
   Removal and installation of headlights
   Removal and installation of the lateral repeater of turns
   Removal and installation of an additional stoplight
   Removal and installation of a back lamp
   Removal and installation of a lamp of illumination of registration plate
   Removal and installation of plafonds of internal lighting
   Removal and installation of a control panel
   Removal and installation of the understeering switch
   Removal and installation of switches of a forward door
   Removal and installation of the switch of light
   Removal and installation of the switch of a window regulator in a back door
   Removal and installation of the switch of a trunk lid
   Removal and installation of the switch of the parking brake
   Removal and installation of the switch of illumination of a ware box
   Removal and installation of switches of the central console
   Removal and installation of the radio receiver / navigation device / CD changer
   Removal and installation of loudspeakers
   Removal and installation of antennas
   Removal and installation of the tank of liquid of the windscreen washer/electric motor of the pump
   Removal and installation of the electric motor of screenwash
   Removal and installation of the electric motor on back glass (Station wagon)
   The uniform lock - the general information
   Removal and installation of a locking element of a cover of a fuel tank
   Digital tire of data of CAN
   + Schematic diagrams of electric equipment






Diagnostics of malfunctions of onboard electric equipment - the general information

Procedures and codes of diagnostics of systems of electronic control are considered in the Head of System of electric equipment of the engine.

The electric component, various switches, the relay, electric motors, safety locks, fusible inserts or breakers of a contour concerning this component, and also the conducting and electric sockets serving for connection of a component with the battery and mass of a body can be a part of a typical electric contour. For simplification of a problem of search of malfunctions of electric contours at the end of the Management schematic diagrams of electric connections are enclosed.

Before starting works on elimination of malfunctions any of electric contours, attentively study the corresponding scheme as much as possible to have a clear view of its functional purpose. Narrowing of a circle of troubleshooting is usually run due to the gradual identification and an exception which are normally functioning a component of the same contour. At simultaneous failure at once several component or contours is the most probable cause of refusal burn-out of the corresponding safety lock or violation of grounding (different contours in many cases can become isolated on one safety lock or the plug of weight).

Refusals of electric equipment often are explained by the elementary reasons, such as corrosion of plugs, failure of a safety lock, combustion of a fusible insert or defect of the relay of switching. Make visual check of a condition of all safety locks, conducting and electric sockets of a contour before starting more concrete check of serviceability its component.

In case of application for troubleshooting of diagnostic units carefully plan according to the enclosed electric circuits in what points of a contour and in what sequence it is necessary to connect the device for the purpose of the most effective detection of defect.

The tester of electric chains or the voltmeter (12 V a control lamp with a set of connecting wires can be also used), the indicator of conductivity of a piece of a contour (sampler) including a bulb, own power supply and a set of connecting wires are among the main diagnostic units. Besides, it is always necessary to have a set of the wires for start of the engine from an auxiliary source equipped with clips like crocodile in the car and, it is desirable, the contour breaker which can be applied to shunting and connection various an electric equipment component in the course of diagnostics of a contour. As it was already mentioned above before starting check of a chain by means of the diagnostic equipment, determine by schemes of a place of its connection.

Verification of tension

Verifications of tension are made in case of violation of functioning of a contour. Connect one of wires of a tester of electric chains or to a negative pole of the battery, or to well grounded car body point. Other wire of a tester connect to the plug of the electric socket of a contour, preferably the next to the battery or to a safety lock. If the control lamp on a tester lights up, tension on this piece of a chain takes place that confirms serviceability of a contour between this plug and the battery. Continuing to work in a similar manner, investigate the contour rest. Detection of lack of tension speaks about existence of malfunction between this point of a contour and the last from checked earlier (where tension was present). In most cases weakening of electric connections and violation of quality of contacts is a cause of failure.

Remember that food on some of contours of onboard electric equipment moves only in provisions of the ASS ignition key (Parking) or "RUN" (Movement).

Searches of short circuit

One of methods of searches of short circuit is extraction of a safety lock and connection instead of it of a lamp sampler or the voltmeter. Tension in a contour has to be absent. Pull conducting, watching a lamp sampler. If the lamp starts blinking, somewhere in this plait there is a short circuit on weight which is perhaps caused by wiping of isolation of a wire. Similar check can be made for each of a contour component, including switches.

Check of serviceability of grounding

This check is made for the purpose of determination of reliability of grounding of a component. Switch-off the battery and connect one of wires of the lamp sampler equipped with the independent power supply to obviously well grounded point. Connect other wire of a lamp to the checked plait or the plug. If the lamp lights up, grounding as it should be (and vice versa).

Conductivity verifications

Check is made for the purpose of identification of breaks of an electric chain After power off of a contour check it by means of the lamp sampler equipped with the independent battery. Connect sampler wires to both ends of a contour (or by the "power" end (+) and well grounded body point) if the control lamp lights up, break in a contour is absent. Refusal of inclusion of a lamp testifies to violation of conductivity of a chain. Similarly it is possible to check and serviceability of the switch, having connected a sampler to its plugs. At transfer of the switch to the situation "Vkl" the control lamp sampler has to light up.

Break localization

At diagnostics of the break of a contour suspected on existence visually to find a cause of defect it appears quite difficult as survey of plugs on existence of corrosion or violation of quality of their contacts is complicated in a type of limitation of access to them (usually plugs are closed by the socket case). Sharp or a plait of its wires in many cases leads twitchings of the case of the socket on the sensor to conductivity restoration. Do not forget about it in attempts of localization of a cause of failure of the contour suspected on break. Unstably arising refusals can have the reason oxidation of plugs or violation of quality of contacts.

Diagnostics of malfunctions of electric chains does not represent a stubborn task on condition of a clear idea at all that current arrives to all electric loadings (a lamp, an electric motor, etc.) from the battery on wires via switches, the relay, safety locks, fusible inserts, and then comes back to the battery through the mass of the car. Any problems connected with refusal of electric equipment can have the reason only interruptions in supply on them electric current from the battery or its return to it.