Diagnosis/troubleshooting PSM 5.7

NOTE: The following troubleshooting applies to PSM 5.7 as of model year 2001.

DIAGNOSIS/TROUBLESHOOTING PSM 5.7 (FAULT CODE 5520)

Work instruction			Display OK	If not OK
1	Check CAN bus between DME control module and Tiptronic control module for short circuit to B+	Switch off ignition Pull plug off the DME control module Pull plug off the Tiptronic control modules Switch on ignition Measure voltage between Tiptronic control module plug pin L and ground	< 0.3V Step 2	Short circuit to B+ in the CAN wiring harness between Tiptronic control module plug pin L and DME control module plug pin B3 ->End
2	Check CAN bus between DME control module and Tiptronic control module for short circuit to B+	Measure voltage between Tiptronic control module plug pin H and ground	< 0.3V Step 3	Short circuit to B+ in the CAN wiring harness between Tiptronic control module plug pin H and DME control module plug pin B4 ->End
3	Check CAN bus between DME control module and Tiptronic control module for short circuit to ground	Switch off ignition Measure resistance between Tiptronic control module plug pin H and ground	Step 4	Short circuit to ground in the CAN wiring harness between Tiptronic control module plug pin H and DME control module plug pin B4
4	Check CAN bus between DME control module and Tiptronic control module for short circuit to ground	Measure resistance between Tiptronic control module plug pin L and ground	Step 5	Short circuit to ground in the CAN wiring harness between Tiptronic control module plug pin L and DME control module plug pin B3
5	Check CAN bus between DME control module and Tiptronic control module for short circuit	Measure resistance between Tiptronic control module plug pin H and pin L	Step 6	Short circuit in the CAN wiring harness between Tiptronic control module plug pin H and pin L and DME control module plug pin B3 and B4 ->End
6	Check CAN bus between DME control module, instrument cluster, PSM control module and PSM steering-angle sensor for short circuit to B+	Pull off the following plugs: PSM control module plug, PSM steering-angle sensor plug and instrument cluster control module plug Switch on ignition Measure voltage between DME control module plug pin D36 and ground	< 0.3V Step 7	Short circuit to B+ in CAN wiring harness between DME control module plug pin D36, instrument cluster plug pin A15, PSM control module plug pin A24 and PSM steering-angle plug pin A2 ->End
7	Check CAN bus between DME control module, instrument cluster, PSM control module and PSM steering-angle sensor for short circuit to B+	Measure voltage between DME control module plug pin D37 and ground	< 0.3V Step 8	Short circuit to B+ in CAN wiring harness between DME control module plug pin D37, instrument cluster plug pin A31, PSM control module plug pin A40 and PSM steering-angle plug pin A1 ->End
8	Check CAN bus between DME control module, instrument cluster, PSM control module and PSM steering-angle sensor for short circuit to ground	Switch off ignition Measure resistance between DME control module plug pin D37 and ground	Step 9	Short circuit to ground in CAN wiring harness between DME control module plug pin D37, instrument cluster plug pin A31, PSM control module plug pin A40 and PSM steering-angle plug pin A1 ->End
9	Check CAN bus between DME control module, instrument cluster, PSM control module and PSM steering-angle sensor for short circuit to ground	Measure resistance between DME control module plug pin D36 and ground	Step 10	Short circuit to ground in CAN wiring harness between DME control module plug pin D36, instrument cluster plug pin A15, PSM control module plug pin A24 and PSM steering-angle plug pin A2 ->End
10	Check CAN bus between DME control module, instrument cluster, PSM control module and PSM steering-angle sensor for short circuit	Measure resistance between DME control module plug pin D36 and DME control module plug pin D37	Step 11	Short circuit in CAN wiring harness ->End
11	Check CAN bus between DME contol unit and PSM control unit for open circuit	Measure resistance between DME control module plug pin D36 and PSM control module plug pin 24	< 5 Step 12	Open circuit in CAN wiring harness to the PSM control module ->End
12	Check CAN bus between DME contol unit and PSM control unit for open circuit	Measure resistance between DME control module plug pin D37 and PSM control module plug pin 40	< 5 Step 13	Open circuit in CAN wiring harness to the PSM control module ->End
13	Check control units	Push on all control module plugs Disconnect the control modules one after the other and check whether the CAN data bus (drive) fault has been remedied	Replace the last control module to be disconnected ->End