Wiring and Components, Checking With Test Box 105 Pin (V.A.G 1598/42)

Wiring and Components, Checking with Test Box 105 Pin (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 105 Pin (V.A.G 1598/42)

• Connector Test Set (V.A.G 1594 C)

• Voltage Tester (V.A.G 1527 B)

• Portable Multimeter (V.A.G 1526 C)

• The test box has 105 terminals. The connection cable can be separated from the test box. This means that as new Engine Control Module (ECM) connectors are introduced in the future, only a new cable must be designed and no longer the entire test box.

• 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 -.

• 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 -.

• 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 electronic engine control 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.

• Always use (V.A.G 1594 C) to connect measuring equipment (for example (V.A.G 1527 B) , (V.A.G 1526 C) , etc.)


To avoid damaging electronic components, switch to the corresponding measuring range and observe all test conditions before connecting the test leads.

The ECM must be removed to disconnect the ECM multi-pin connectors. Refer to => [ Engine Control Module (J623) ] Engine Control Module (J623).

- Connect the (V.A.G 1598/42) to the wiring harness connector. Attach the ground clip on the test box to the battery negative cable. The procedures will indicate whether the ECM is to be connected to the test box.

- Perform test as described in relevant repair sequences.

Installing the ECM

Install in reverse order of removal.

- Thereafter, the ECM 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.

- Check the Diagnostic Trouble Code (DTC) memory and erase if necessary.