Possible Causes
WARNING: This page is about a different car, the 1996 Volvo 850. However, it is still accessible from the selected car via links, so may be relevant.
This DTC is always stored with DTC 446 (PAIR valve leakage) or DTC 448 (PAIR pump, flow too low). If scan tool indicates PERMANENT FAULT, LEAKAGE, or INTERMITTENT FAULT, LEAKAGE, go to DTC 446 - PULSED SECONDARY AIR INJECTION SYSTEM (PAIR) PUMP FLOW FAULT . If scan tool indicates PERMANENT FAULT, FLOW TOO LOW, or INTERMITTENT FAULT, FLOW TOO LOW, go to DTC 448 - PULSED SECONDARY AIR INJECTION SYSTEM (PAIR) PUMP FLOW FAULT .