Antilock Brakes / Traction Control Systems: Service Precautions

Notes On Fault Memory / Troubleshooting

Never pull off or push on the control module connector with the ignition switched on.

Faults may be stored under certain circumstances if, for troubleshooting purposes, electrical connections are loosened or disconnected with the ignition switched on.

The ABS MIL or TC MIL can light up although no fault is stored in the fault memory. The following faults are possible in this case:
- Mechanical switching contacts (arrows) in the control module connector bent. As a consequence, these contacts are permanently connected to ground (ground of PIN 19 connected to PIN 20 and PIN 21).

Explanation: Normally, these contacts are grounded only when the connector is pulled off. This causes the ABS MIL or the TC MIL to be activated when the engine is running.

- When the engine is running, the "terminal 61" signal is missing at the control module. This can be checked with the Porsche System Tester 2 via the Input signals menu.







Work after fault elimination
The fault memory must be erased after a fault occurs in the anti-lock brake system and is eliminated. Then perform a short test drive and perform a TC control operation, taking the road conditions into consideration. Then read out the fault memory again.

Fill/bleed the system after the hydraulic unit has been replaced or removed and reinstalled.

Then perform a system test.