With Generic Scan Tool

Terminal Resistance For CAN-Bus, Checking
The Engine Control Module (ECM) communicates with all databus-capable control modules via a CAN-Bus.

These databus-capable control modules are connected via two data bus wires which are twisted together (CAN_High and CAN_Low), and exchange information (messages). Missing information on the CAN-Bus is recognized as a malfunction and stored.

Trouble-free operation of the CAN-Bus requires that it have a terminal resistance. This central terminal resistor is located in the Engine Control Module (ECM).

Recommended special tools and equipment







- VAG1526A hand multimeter
- VAG1594A connector test kit
- VAG1598/31 test box

Test requirement:
- Ignition switched off.

Test sequence
- Connect test box to the Engine Control Module (ECM); wiring harness is not connected. Test Box, Connecting For Wiring Test
- Check the central termination resistor in the Engine Control Module (ECM).
- Connect multimeter between terminal 58 and 60 of test box for resistance measurement.
- Specified value: 60 ... 72 Ohm

If the specification is exceeded or not met:
- Replace Engine Control Module (ECM).

If specified value is obtained:
- Disconnect test box from Engine Control Module (ECM).
- Connect test box to control module wiring harness.
- Check CAN data bus wires for short circuit to each other:
- Connect multimeter between terminal 58 and 60 of test box for resistance measurement.
- Specified value: Infinite Ohm (no continuity)

- If necessary, repair wire connection according to wiring diagram.