Checking Instructions/CAN Data Bus

Checking Instructions/CAN Data Bus

Diagnostic conditions
- Ignition on
- Internal control module function test

Possible cause of fault

1. No data can be sent/received via CAN data bus (CAN data bus OFF):
One of the following errors is memorised in all control modules: CAN drive (high/low)/ CAN infotainment (high/low)/ CAN comfort OFF (high/low)

Use the table Cause of fault 1 for troubleshooting.
- Short circuit to B+
- Short circuit to ground
- Short circuit with respect to each other (high and low wires)
- Confused high and low wires (wrong slot in connector, or faulty wires confused during repairs)

2. Expected control module message missing/no communication possible with control module:
Read out the fault memory in the gateway and localise the error via the memorised error using the CAN topology. Refer to Circuit diagram

Use the table Cause of fault 2 for troubleshooting.
- The corresponding control module does not have a power/ground supply
- The corresponding control module does not function
- CAN data bus on affected control module interrupted

Affected pins
The measurements to be taken are listed in the work instruction below. The measurements must be implemented using the pin assignment shown in the table below, while taking the relevant control module and CAN data bus into account.

Control Module 1 - 15:

Control Module 16 - 31:

Diagnosis/troubleshooting, CAN data bus

NOTE: Faults can only be located quickly and effectively with the help of the CAN topology and CAN networking. Refer to Circuit diagram

Cause of error 1, no data can be sent/received via CAN data bus (CAN data bus OFF):

Work Instruction 1:

Work Instruction 1 - 2:

Work Instruction 3 - 7:

Cause of error 2, expected control module message missing/no communication possible with control module:

NOTE:
- Before replacing the control module, the ground connections, power supply and plug connections on the control module must be checked.
- When replacing the control unit, observe the coding.
- After the test drive, read out the fault memory with the Porsche System Tester II 9588 again. Additional causes of faults that could damage the control module should be detected and remedied.