Wiring and components, checking with Test box V.A.G 1598/42

WARNING: This page is about a different car, the 2009 Audi A4, 2008 Audi A4, 2007 Audi A4, 2006 Audi A4, and 2005 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

Special tools, testers and auxiliary items required

Fig 1: V.A.G 1598/39-1/2 Adapter Cables

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Adapter cable V.A.G 1598/39

Fig 2: V.A.G 1598/42 Test Box

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Test box V.A.G 1598/42

Fig 3: Connecting Test Box V.A.G 1598/42 To Wiring Harness With Adapter Cable V.A.G 1598/39-1 Or Adapter Cable V.A.G 1598/39-2

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NOTE:

The test box V.A.G 1598/42 is designed with 105 terminals. It can be connected to the engine control module (ECM) via 2 different adapter cables.
The engine control module (ECM) is connected to the vehicle electrical harness via a 60-pin connector and a 94-pin connector.
For testing at the 60-pin connector, the adapter cable V.A.G 1598/39-1 is connected to the test box with connector "A". Components of the 60-pin harness connection → Electrical Wiring Diagrams, Troubleshooting and Component Locations.
For testing at the 94-pin connector, the adapter cable V.A.G 1598/39-2 is connected to the test box with connectors "A" and "B". Components of the 94-pin harness connection → Electrical Wiring Diagrams, Troubleshooting and Component Locations.
The test box V.A.G 1598/42 is designed so that it can be connected simultaneously to the engine control module harness and the engine control module itself. This is advantageous because electronic engine control remains fully functional (e.g. measurement of signals with engine running) when the test box is attached.
The procedure will indicate whether the engine control module is to remain connected to the test box or not.
To connect measuring instruments (e.g. Voltage Tester V.A.G 1527B , Multimeter V.A.G 1526C etc.) always use Connector Test Set V.A.G 1594C.

The engine control module (ECM) must be removed to disconnect the ECM harness connectors → Engine Control Module (ECM), removing and installing .

CAUTION: To avoid damaging electronic components, set measuring range before connecting test leads and observe all test requirements.

Fig 4: Connecting Test Box V.A.G 1598/42 To Wiring Harness With Adapter Cable V.A.G 1598/39-1 Or Adapter Cable V.A.G 1598/39-2

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Connect Test Box V.A.G 1598/42 to wiring harness with adapter lead V.A.G 1598/39-1 or adapter lead V.A.G 1598/39-2. Clamp test box Ground (GND) clip to battery negative terminal. The procedure will indicate whether engine control module is to be connected to test box or not.
Perform test as described in corresponding repair procedure.
After completing test, install engine control module (ECM) → Engine Control Module (ECM), removing and installing .

After installing Engine Control Module (ECM), the following work steps must be performed:

Check DTC memory and, if necessary, erase it. After DTC memory is erased, a readiness code must be generated for engine control module using operating mode "Guided Fault-Finding".