Checking bus system: Audi A3 1.8 (ARX, ARY, AUM, AUQ)

🧭 Before you start

Fits: Audi A3 (8L, 1996–2003)

Don't miss

• Connect up the vehicle diagnostic and service information systemVAS 5052 and select the engine electronics control unit. When doing this, the ignition must be switched on.
• The measured value blocks 125 and 126 indicate the drive system data bus users.

🔧 Engine codes this applies to

📋 Procedure

1. Connect up the vehicle diagnostic and service information systemVAS 5052 and select the engine electronics control unit. When doing this, the ignition must be switched on.
2. Select the function "“Read measured value block”". [Note: The measured value blocks 125 and 126 indicate the drive system data bus users.]
3. Select "“Display group number 125”".
4. Check the displays in zones 1 to 4. The display shows the control units capable of CAN communication with the engine control unit:
5. Perform the same check for display group number 126.

6. Press the → key.
7. Select the function "“End output”".
8. Select "“Automatic test sequence”".
9. Check whether the vehicle has been fitted with the correct engine control unit and other control units with CAN capability (part no. and code).
10. Check for firm attachment of the multi-pin connectors of the control units.
11. Check the CAN bus system.

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