Wiring and Components, Checking with Test Box (V.A.G 1598/42)

Wiring and Components, Checking with Test Box (V.A.G 1598/42)

Special tools, testers and auxiliary items required

• Adapter Cable (V.A.G 1598/39-1)

• Adapter Cable (V.A.G 1598/39-2)

• Test Box (V.A.G 1598/42)

• The (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 smaller of the two connectors on the ECM is assigned with terminals 1 to 60. The larger of the two connectors is assigned with terminals 1 to 94.






• For testing at the 60-pin harness connection, the (V.A.G 1598/39-1) is connected to the test box with connector "A". Components of the 60-pin harness connection.

• For testing at the 94-pin harness connection, the (V.A.G 1598/39-2) is connected to the test box with connectors "A" and "B". Components of the 94-pin harness connection.

• The (V.A.G 1598/42) is designed so that it can be connected simultaneously to the ECM harness and the ECM itself.

• This is advantageous because ECM remains fully functional (for example measurement of signals with engine running) when the test box is attached.

• The procedures will indicate whether the ECM is to remain connected to the test box or not.

The ECM must be removed to disconnect the ECM harness connectors. Refer to => [ Engine Control Module ] Service and Repair.


Risk of destroying electrical components.

• Before connecting test leads, switch on respective measuring range and observe test conditions.

- Connect (V.A.G 1598/42) to wiring harness with (V.A.G 1598/39-1) or (V.A.G 1598/39-2). Clamp test box Ground (GND) clip to battery negative terminal. The procedure will indicate whether the ECM is to be connected to the test box or not.

- Perform test as described in relevant repair sequences.

Installing the ECM

Install in reverse order of removal.

- Thereafter, the engine control module must be equipped with the protective housing.

- Clean threaded holes for shear bolts of locking compound residue. Cleaning can be performed with a thread cutter (tap).

- Always use new shear bolts.

The procedures to follow after connecting the new ECM are described in Guided Fault Finding and Guided Functions.

• When ending Guided Fault Finding, the tester attempts to erase the DTC memory of all control modules. If this is not successful, the remaining DTCs stored in memory must be corrected until all DTCs can be erased.