Connecting Adapter Cable (121-Point) VAG1598/31 to Engine Control Module (ECM) J623.

Fig 1: V.A.G 1598/31 Test Box

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Special tools, testers and auxiliary items required

NOTE:

The test box V.A.G 1598/31 is designed so that it can be connected simultaneously to the engine control module harness and the engine control module itself.
This makes it possible for the electronic engine control to remain fully functional with the test box attached (e.g. measurement of signals with engine running).
To connect measuring instruments (e.g. Voltage Tester VAG1527B, multimeter V.A.G 1526 B etc.) always use Connector Test Set VAG1594C.

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

The Engine Control Module (ECM) J623 must be removed to disconnect the ECM harness connectors → Engine Control Module (ECM) J623, removing and installing .

Connect Adapter Cable (121-Point) VAG1598/31 to Engine Control Module (ECM) J623 wiring harness. Clamp Adapter Cable (121-Point) VAG1598/31 Ground (GND) clip to the battery negative terminal. The procedure will indicate whether the 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) J623 → Engine Control Module (ECM) J623, removing and installing .

After installing Engine Control Module (ECM) J623, the following work steps must be performed: