Fault Conditions

P0420

Three Way Catalytic Converter. Malfunction.







Fault symptoms
^ CHECK ENGINE.

On-Board Diagnostics

Type of diagnosis:
^ Once per driving cycle. Interrupted when fault criteria fulfilled or OK reported.
Restarts next driving cycle.

Enable criteria:
^ General conditions for this trouble code: Atmospheric pressure must exceed 72 kPa and the engine coolant and intake air temperatures must exceed -7 degree C.
^ Ignition of front catalytic converter: Engine running. Mass air flow has exceeded 5 g/s (aut 7 g/s) during an accumulative time of 120 s. The mass air flow has exceeded 20 g/s during an accumulative time of 18 s. No engine braking with fuel shut-off for longer than 10 s. No idling for longer than 40 s.
Evaluation of catalytic converter: More than 200 sec. since start. Coolant temperature above 70 degree C. Speed 40-115 km/h. Accelerator pedal depressed. Engine speed 1270-2540 rpm (aut 1200-2100). Engine load 100-500 mg/c. Voltage transitions in oxygen sensor 2 are corrected with regard to load and engine speed and are accumulated under approved voltage periods for oxygen sensor 1*). When the voltage transitions have been corrected and accumulated for 20 sec their mean value is calculated.
*) Accepted periods have 30-80 % pulse ratio (+trigger).

Fault criteria:
^ Mean value of voltage transitions exceeding a calibrated value.

Dependents:
^ P0100, P0102, P0103, P0116, P0117, P0118, P0131, P0132, P0134, P0138, P0140, P0336, P0337, P0501, P0502, All throttle faults.

System reaction to a fault:
^ None.

OK report:
^ Diagnosis performed once and fault criteria not fulfilled.

Fault handling: (For more information, Fault Handling III, Other Emission-Related Components and Function)

^ Type III.

Diagnostic help
The capacity of the catalyst can be reduced temporarily or permanently for the following reasons:
^ Lead or sulphur in the fuel.
^ Fuel additives.
^ Engine oil additives.

Functions in the diagnostic tool related to the fault:
^ Diagnostic status for the diagnosis.

For more information refer to description of read values, Menu Read Values