Diagnosis Procedure
1 Check function of oxygen sensor.
1. Heat the oxygen sensors (road test car under load or run engine without load at high rpm).
2. Connect Porsche System Tester 2 or scan tool and read voltage of oxygen sensor 1 after TWC.
Display: Voltage fluctuations between 100 mV and 800 mV.
- Oxygen sensor OK.
2 Check wiring harness.
1. Remove oxygen sensor connector.
2. Connect special tool 9637 to wiring harness (DME control module connector).
3. With an ohmmeter, measure resistance between special tool 9637, pin II/11, and oxygen sensor connector, pin 3.