Diagnostic Procedure For the Bus Wiring Harness - I

Diagnostic Procedure For The Bus Wiring Harness







- The cause of the fault is an open circuit on bus+ or bus- (if only the Trionic or TCM and Trionic are missing, the fault could also be due to a short circuit in the P bus).







- Turn the ignition switch to the ON position.
- Select: All systems/Bus configuration in the diagnostic tool's main menu.

Checking The Wiring Harness
Jiggle the leads and in-line connectors at several places and in different directions to reveal intermittent breaks and short circuits in the wiring harness. Observe the multimeter, test lamp or diagnostic tool while doing this.

- The diagnostic Instrument shows OK when communication starts.
- If necessary, disconnect one control module at a time to trace a possibly faulty one.
- The potential between bus+ and ground and between bus- and ground should be 2-3 V. All control modules put out this voltage.
- Rectify the fault.

After performing this procedure Final Check