Diagnosis/troubleshooting PSM 5.3

NOTE: The following troubleshooting applies for PSM 5.3; 911 Carrera 4; model year 1999.

DIAGNOSIS/TROUBLESHOOTING PSM 5.3 (FAULT CODE 5527)

Work instruction			Display OK	If not OK
1	Check CAN bus between PSM control module and DME control module for short circuit to B+	Switch off ignition Pull plug off the PSM control module Pull plug off the PSM steering angle sensor Pull plug off the DME control module Switch on ignition Measure voltage between PSM control module plug pin 61 and ground	< 0.3V Step 2	Short circuit to B+ in the CAN wiring harness between PSM control module plug pin 61 and DME control moduel plug IV pin 36 ->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 86 and ground	< 0.3V Step 3	Short circuit to B+ in the CAN wiring harness between Tiptronic control module plug pin 86 and DME control module plug II pin 4 ->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 86 and ground	Step 4	Short circuit to ground in the CAN wiring harness between Tiptronic control module plug pin 86 and DME control module plug II pin 4
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 85 and ground	Step 5	Short circuit to ground in the CAN wiring harness between Tiptronic control module plug pin 85 and DME control module plug II pin 3
5	Check CAN bus between DME control module and Tiptronic control module for short circuit	Measure resistance between Tiptronic control module plug pin 86 and pin 85	Step 6	Short circuit in the CAN wiring harness between Tiptronic control module plug pin 86 and pin 85 and DME control module plug II pin 3 and pin 4 ->End
6	Check CAN bus between DME control module, 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 IV pin 36 and ground	< 0.3V Step 7	Short circuit to B+ in the CAN wiring harness between DME control module plug IV pin 36 and PSM control module plug pin 61 and PSM steering angle connector pin 2 ->End
7	Check CAN bus between DME control module, PSM control module and PSM steering-angle sensor for short circuit to voltage	Measure voltage between DME control module plug IV pin 37 and ground	< 0.3V Step 8	Short circuit to B+ in the CAN wiring harness between DME control module plug IV pin 37 and PSM control module plug pin 63 and PSM steering angle connector pin 1 ->End
8	Check CAN bus between DME control module, PSM control module and PSM steering-angle sensor for short circuit to ground	Switch off ignition Measure voltage between DME control module plug IV pin 37 and ground	Step 9	Short circuit to ground in the CAN wiring harness between DME control module plug IV pin 37 and PSM control module plug pin 63 and PSM steering angle connector pin 1 ->End
9	Check CAN bus between DME control module, PSM control module and PSM steering-angle sensor for short circuit to ground	Measure voltage between DME control module plug IV pin 36 and ground	Step 10	Short circuit to ground in the CAN wiring harness between DME control module plug IV pin 36 and PSM control module plug pin 61 and PSM steering angle connector pin 2 ->End
10	Check CAN bus between DME control module, PSM control module and PSM steering-angle sensor for short circuit	Measure resistance between DME control module plug IV pin 36 and DME control module plug IV pin 37	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 IV pin 36 and PSM control module plug pin 61	< 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 IV pin 37 and PSM control module plug pin 63	< 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