P0492

P0492

Secondary Air Injection System, Bank 2 - Insufficient Flow

Diagnostic conditions
- Intake air temperature 4.5 - 60 °C (40 - 140 °F)
- Engine temperature 4.5 - 102 °C (40 - 216 °F)
- Mass air flow 36 - 150 kg/h
- Engine starting temperature less than 42 °C (108 °F)
- Altitude correction factor greater than 0.75
- Oxygen sensors 1 and 2 ahead of TWC are ready for operation
- The secondary air injection pump is switched on
- Diagnosis has not yet taken place during this cycle

Possible cause of fault
- Electrical fault in power supply or line between relay and secondary air injection pump
- Secondary air injection pump relay mechanically faulty
- Mechanical fault in electrical secondary air valve
- Pneumatic secondary air valve faulty/sluggish
- Electrical fault in secondary air injection pump
- Mechanical fault in secondary air injection pump or secondary air injection pump blocked
- Vacuum system leaking
- Air hose to secondary air injection pump slipped off or constricted

Affected terminals
- Secondary air injection pump relay pin 5 to secondary air injection pump pin 1
- Power supply for secondary air injection pump relay pin 3
- Ground supply line for secondary air injection pump pin 2

Diagnosis/troubleshooting

NOTE:
- The secondary air volume is measured using the oxygen sensors. This is done by recording the oxygen injected into the exhaust gas via the secondary air injection pumps and comparing the recorded value to a limit value.
- Secondary air diagnosis can be activated with the Porsche System Tester 2 in the "Short test" menu.

Part 1:

Part 2:

996 Turbo vacuum system







996 Carrera Secondary Air System up to Model Year 1999







996 Carrera Secondary Air System as of Model Year 2000