1 - Carry out raw emission measurement:
1. Reset mixture adaptation values (disconnect battery)
2. Disconnect oxygen sensors
If the difference between bank 1 and bank 2 is greater than approx. 0.8 %, then
1 - Set the camshaft control times again.
2 - Road test vehicle. The mixture adaptation values must be normal.
VarioCam does not switch over completely
The VarioCam does not switch over completely from power to torque valve timing.
An indication of this problem is misfiring detected by the DME control module in the range of 1200 - 1500 rpm occurring in an entire bank.
The mixture adaptation values are normal.
Remedy:
1 - Replace VarioCam.
2 - Road test vehicle.
Other possible fault causes
- worn camshafts
- leaking valves
- faulty piston rings
If opposing cylinders have misfiring, the cause could be the sensor wheel.
If valve lift faults are suspected, perform the system test for large lift and the system test for small lift with the Porsche System Tester 2.
NOTE: If the battery was disconnected, at least range 1 of sensor wheel adaptation must be adapted before troubleshooting is carried out; see
actual values explanation.
Diagnosis/Troubleshooting
NOTE: If there is a lot of oil in the engine, check that the oil filler tube and cap are tight.