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Electrical Testing


- If the On Board Diagnostic (OBD) sequence does not provide any indication of the source of the malfunction, work through all of the electrical test steps.
- If the OBD sequence identifies the source of the malfunction, only carry out the test steps recommended in the DTC table (specific testing).

Test requirements
- The "Automatic Test Sequence" was carried out and it was determined that the Transmission Control Module (TCM) and Engine Control Module (ECM) only contain DTC's relating to ABS.
- Connect the VAG 1 551 Scan Tool (ST) and select the address word 00 with ignition switched on;
- After completing electrical test, check and erase DTC memories of Transmission Control Module (TCM) and Engine Control Module (ECM).





- Multi-pin harness connector for ABS control module -J104- in proper condition, with no bent, broken or corroded terminals. Replace any damaged terminals using VAS1978 wiring repair kit.

Note: The operation manual for the VAS1978 wiring harness repair kit generally forbids the repair of any lines in the ABS or related systems. This rule only pertains to the shielded lines in these systems.

- Ignition and electrical consumers switched off before beginning testing (headlights, lighting, fan, etc.).
- For steps 13 through 16, raise the vehicle until the wheels rotate freely. On vehicles with manual transmission put the gear shift lever in neutral. On vehicles with automatic transmission move the selector lever to position "N".

Required special tools and test equipment:
- VAG1598/20 test box
- VAG1594 connector test kit
- VAG1526 Multimeter
- VAG131OA Pressure gauge

Connecting the VAG1598/20 test box and checking the ABS, ABS/EDL or ASR system
- Switch ignition off.
- Remove ABS control module -J 104-.
- Disconnect multi-pin connector from ABS control module-J104-.
- Check multi-pin connector between harness connector and ABS control module -J104-.





The socket designations on the VAG1598/20 test box are identical to the terminal designations on the ABS control module -J104- and on the wiring harness connector.
- Connect VAG1598/20 test box to multi-pin connector of ABS wiring harness.

Terminals 1-7:




Terminals 9-15:




Terminals 18-29:




Terminals 31-36:




Terminals 37-47:




Terminals 47-55:





Terminal assignment of multi-pin connector for wiring harness / ABS control module (w/EDL) -J1 04

Notes: For test table:

- The socket designations of the VAG1598 test box are identical to the terminal designations of the ABS control module (w/EDL) -J104- in the wiring diagram. Incorrect test procedures can cause damage to the system. Do not bridge any terminals other than those listed in the table.
- Specified values refer to readings on the VAG1526 and are not necessarily applicable for other test units.
- If the measured values do not match specifications, carry out the corrective actions listed on the right side of the table.
- If values are obtained, also check wiring for intermittent loose terminals and short circuit to B+ and Ground (GND). This applies especially to sporadic malfunctions.
- Use the VAG1594 connector test kit for checking continuity (bridges).
- If the measured values only differ slightly from the specifications, clean the sockets and harness connectors of the testers and adapter leads (using contact spray G 000 700 04) and repeat the test. Before replacing actual components, check wiring and connections once more.

This is especially important if the specification for a resistance test is under 10 Q.
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