P1143

P1143

Oxygen Sensing Error by means of Short Test, Bank 2 - Above Limit

Diagnostic conditions
- Battery positive voltage between 10 V and 16 V
- Time elapsed after engine start-up greater than 10 seconds
- Fuel Supply System short test performed using the Porsche System Tester ll 9588

Possible cause of fault
- Incorrect main charge signal
- Fuel pressure too high
- Fuel injector leaking
- EVAP canister purge valve continually open
- DME control module faulty

Diagnosis/troubleshooting

NOTE:
- If connector A is disconnected from the DME control module and the ignition is or was switched on, the DME Control Module Time-out fault is recorded in many control modules.
- If control module connector A was disconnected from the DME in the course of troubleshooting or if the voltage supply was interrupted elsewhere (battery, fuse), the throttle adjusting unit must be adapted.
- If this fault is set, both mass air flow sensors must essentially be checked since the main charge signal is calculated from both signals.
- If P0445 - Below Limit is stored in memory, correct this fault first.
- An open EVAP canister purge valve can lead to the lean threshold being reached.
- The short tests Fuel Supply System - Idle Speed and Fuel Supply System - Partial Load are designed in such a way that faults in the fuel supply system (oxygen sensing system) can be detected even without a road test. A fault entry following the short test means that a normal fault entry would have been recorded even after a longer road test. The troubleshooting procedure is therefore identical to that specified in the reference chapters.

Step 1-3: