Audi A6 Typ 4G: On Board Diagnostic System (OBD)

Malfunction Indicator Lamp (MIL)

The Malfunction Indicator Lamp (MIL) in the instrument cluster is part of the On-Board Diagnostic (OBD II) system.

The warning/indicator light illuminates when the ignition is switched on and goes out after the engine starts and the idle has stabilized. This indicates that the MIL is working properly.

If the light does not go out after the engine is started, or illuminates while you are driving, a malfunction may exist in the engine system. If the light illuminates, the catalytic converter could be damaged.

Continue driving with reduced power (avoiding sustained high speeds and/or rapid accelerations) and have the condition corrected. Contact your authorized Audi dealer.

If the light illuminates, the electronic speed limiter may also be malfunctioning. An improperly closed fuel filler cap may also cause the MIL light to illuminate.

On-Board Diagnostics

Fig. 14 Location of Data Link Connector (DLC)

On-Board Diagnostics monitors the components of your emission control system. Each monitored component in your engine system has been assigned a code. In case of a malfunction, the component will be identified and the fault stored as a code in the control module memory.

The MIL light may also illuminate if there is a leak in the on-board fuel vapor recovery system.

If the light illuminates after a refuelling, stop the vehicle and make sure the fuel filler cap is properly closed.

In order to make an accurate diagnosis, the stored data can only be displayed using special diagnostic equipment (generic scan tool for OBD).

In order to connect the special diagnostic equipment, push the plug into the Data Link Connector (DLC). The DLC is located to the right of the hood release fig. 14.

Your authorized Audi dealer or a qualified service station can interpret the code and perform the necessary repair.

WARNING

Do not use the diagnostic connector for personal use. Incorrect usage can cause malfunctions, which can increase the risk of a collision!

Electronic speed limiter

Your vehicle may be factory equipped with tires that are rated for a maximum speed of 130 mph (210 km/h). This is less than the maximum speed of your vehicle. To reduce the risk of sudden tire failure and loss of control if the vehicle is operated at excessive speeds, your vehicle also has an electronic speed limiter. The electronic speed limiter prevents your vehicle from going faster than the tire speed rating.

If the engine control unit receives faulty vehicle road speed signals, the Malfunction Indicator Lamp (MIL) will illuminate. If this occurs, contact the nearest authorized Audi dealer for assistance.

S models

Your vehicle's top speed is electronically limited to 155 mph (250 km/h).

If the engine control unit receives faulty vehicle roadspeed signals, the Malfunction Indicator Lamp (MIL) will illuminate. If this occurs, contact the nearest authorized Audi dealer for assistance.

WARNING

Always observe the posted speed limits and adjust your speed to suit prevailing road, traffic and weather conditions. Never drive your vehicle faster than the maximum speed rating of the tires installed.

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