Scan Tool Connecting

Wiring and Components, Checking with Test Box VAG 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 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 (ECM) is connected to the vehicle electrical harness via a 60-pin connector and a 94-pin connector.

• For testing at the 60-pin harness connection, 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.

• For testing at the 94-pin harness connection, 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.

• 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.

• Always use connector test set (V.A.G 1594 C) to connect measuring equipment (e.g. voltage tester (V.A.G 1527 B), portable multimeter (V.A.G 1526 C), etc.)

ECMs must be removed in order to disconnect multi-pin connectors from them.

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

- Switch off ignition.

- Remove rubber seal - 1 - and remove plenum chamber cover - 2 -.





• Both engine control modules are identical. If both engine control modules are removed, they must be marked before removal to prevent them from being interchanged when re-installing.

• Master-ECM 2: e.g. with a "M"

• Slave-ECM 1: e.g. with a "S"

• Item - 1 - faces Engine Control Module (ECM) 2 (J624) (slave).





• Item - 2 - faces Engine Control Module (ECM) (J623) (master).

- Carefully pull cowl grill only as far as necessary out of retainer on windshield.

To increase the difficulty with which the ECM connectors can be accessed, the ECM is secured in a metal housing with retaining tabs and shear bolts.

• Engine Control Module (ECM) (J623), removing and installing, refer to => [ Engine Control Module 1, Master ] Engine Control Module 1, Master

• Engine Control Module (ECM) 2 (J624), removing and installing, refer to => [ Engine Control Module 2, Slave ] Engine Control Module 2, Slave

- Connect 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). Clamp test box Ground (GND) clip to battery negative terminal. The procedure will indicate whether the engine control module is to be connected to the test box or not.





- Perform test as described in the corresponding repair procedure.

Installing engine control module (ECM)

Install in reverse order of removal.

- Thereafter, the engine control module must be equipped with the metal retainer.

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

- Always use new shear bolts.

• 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.