Checking control unit power supply: Audi A3 1.8 (ARX, ARY, AUM, AUQ)

🧭 Before you start

Fits: Audi A3 (8L, 1996–2003)

• Special tools named: V.A.G 1598/31

Don't miss

• Connect the test box V.A.G 1598/31 to the wiring harness to the engine control unit, but do not connect the actual engine control unit .
• The engine control unit receives its positive power supply via contact 3 (terminal 15) and contact 62 (terminal 30).The engine control unit receives its earth supply by way of contacts 1 and 2.

🔧 Engine codes this applies to

📐 43 workshop diagrams for ARX

Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.

📋 Procedure

1. Connect the test box V.A.G 1598/31 to the wiring harness to the engine control unit, but do not connect the actual engine control unit .
2. Switch on ignition. [Note: The engine control unit receives its positive power supply via contact 3 (terminal 15) and contact 62 (terminal 30).The engine control unit receives its earth supply by way of contacts 1 and 2.]
3. Connect up the multimeter (voltage measuring range) as follows:
4. Connect up the multimeter (voltage measuring range) as follows:
5. Switch on ignition.

6. Check the wiring.
7. Connect up the multimeter (voltage measuring range) as follows:
8. Switch on ignition.
9. Check the wiring.
10. Check the Motronic current supply relay J271.

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