800B CDR23: Diagnosis/troubleshooting
DIAGNOSIS/TROUBLESHOOTING (800B CDR23)
| Work instruction |
Display OK |
If not OK |
| 1 |
Check CAN comfort leads, CAN comfort (high) and CAN comfort (low) for short circuit |
- Switch off ignition.
- Remove plug A from instrument cluster.
- Pull plug off the Tiptronic control module.
- Pull plug off the PSM control module.
- Pull off plug on steering-angle sensor.
- Pull plug off the DME control module.
- Measure resistance on plug A of the instrument cluster between pin 15 and pin 31.
- Measure resistance between pin 3 and pin 4 of plug B on the DME control module.
|
Step 2 |
Repair wiring harness
-> End |
| 2 |
Check CAN comfort lead, CAN-high for short to ground |
- Measure resistance between pin 15 and ground of plug A on instrument cluster.
- Measure resistance between pin 3 and ground on plug B of the DME control module.
|
Step 3 |
Repair wiring harness
-> End |
| 3 |
Check CAN comfort lead, CAN-low for short circuit to B+ |
- Switch on ignition.
- Measure resistance between pin 31 and ground of plug A on instrument cluster.
- Measure voltage between pin 3 and ground on plug B of the DME control module.
|
0 V
Step 4 |
Repair wiring harness
-> End |
| 4 |
Determine faulty control unit |
- Switch off ignition.
- Reconnect all plugs to control units.
- Pull off plugs to the control units (except instrument cluster) individually and read out the fault memory of the instrument cluster and check whether the fault has been remedied.
|
The fault is remedied by disconnecting the plug connection of a control unit.
Step 5 |
The fault is still present Step 6 |
| 5 |
- Replace the control module that was last disconnected from CAN comfort
|
-> End |
| 6 |
- Replace instrument cluster
|
-> End |