If resistance is outside specified range:

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2001 Volkswagen Jetta, 2001 Volkswagen Golf, 2000 Volkswagen Jetta, 2000 Volkswagen Golf, and 1999 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.

Remove air cleaner.

Fig 1: Releasing ABS Control Module Connector

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Release ABS Control Module connector and remove.
Check CAN-Bus wiring for short to one another:
Measure resistance between test box sockets 68 + 75:

Specification: ∞ Ω

If specification is not obtained wires are shorted:

Repair short in wiring using wiring diagram: → Electrical Wiring Diagrams, Troubleshooting and Component Locations
Check DTC memory, if necessary, repair any malfunctions.
Erase DTC memory → Diagnostic Trouble Code (DTC) memory, checking and erasing
Display readiness code → Readiness code, displaying . If DTC memory has been erased, readiness code must be reset → Readiness code, setting .

If specification is obtained wires are not shorted:

Fig 2: Connecting Test Box V.A.G 1598/21 To ABS Control Module

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Connect test box V.A.G 1598/21 - 1 - to wiring harness for ABS Control Module J104 - 2 -.
Check CAN-Bus wiring between test box sockets 1598/22 and 1598/21 for open circuit using wiring diagram:

1598/22 - 1598/21
Socket 68 and - socket 10
Socket 75 and - socket 11
Wire resistance: max. 1.5 Ω

Also, check for shorts to battery positive (B+) or Ground (GND).

If no wiring damage is found:

Replace ABS control module. → 45 ANTI-LOCK BRAKE SYSTEM