Fault handling I, catalyst damaging misfiring

WARNING: This page is about a different car, the 2001 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.

If catalyst damaging misfiring occurs, the driver is warned immediately by the CHECK ENGINE lamp flashing at 1 Hz, irrespective of whether the lamp was already on or not. A diagnostic trouble code will be generated at the same time.

For the CHECK ENGINE lamp to go out without any other measures being taken requires 3 consecutive driving cycles under similar operating conditions as when the fault first occurred without the catalyst damaging misfiring returning.

For the diagnostic trouble code to be cleared requires a further 40 fault -free warming -up cycles.

Fault criteria for catalyst damaging misfiring fulfilled

Fig 1: Diagnostic Flow Chart - Catalyst Damaging Misfiring (1 Of 2)
Courtesy of SAAB-SCANIA OF AMERICA, INC.

Dependents are OK
CHECK ENGINE lamp flashing at 1 Hz, diagnostic trouble code generated
Catalyst damaging misfiring ceases
Diagnostic trouble code cleared
CHECK ENGINE lamp goes on continuously

Fig 2: Diagnostic Flow Chart - Catalyst Damaging Misfiring (2 Of 2)
Courtesy of SAAB-SCANIA OF AMERICA, INC.
Catalyst damaging misfiring does not occur for 40 warming -up cycles
Catalyst damaging misfiring does not occur for 3 consecutive driving cycles under similar operating conditions as when the fault first occurred
and
CHECK ENGINE lamp goes out