P0420

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 condition for this diagnostic trouble code: Atmospheric pressure must exceed 72 kPa as well as coolant and intake air temperature must exceed -7 degree C.
- Ignition of front catalyst: Engine running. Air mass flow has exceeded 5 g/s (aut 7 g/s) for an accumulate time of 120 sec. The air mass flow has exceeded 20 g/s for an accumulate time of 18 sec. No motor braking with fuel shut-off for more than 10 sec. No idling longer than 40 sec.

Assessment of catalytic converter: Longer than 200 sec. since start. Coolant temperature above 70 degree C. Vehicle speed 40 - 115 km/h. Accelerator pedal depressed. Engine speed 1270 - 2540 rpm (auto. 1200 - 2100 rpm). Engine load 100 - 500 mg/c. Oxygen sensor 2 voltage changes corrected with respect to load and engine speed and accumulated for during approved voltage periods for oxygen sensor 1 *). When the voltage changes have been corrected and accumulated for 20 sec., their average 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, P0115, P0116, P0117, P0118, P0119, P0131, P0132, P0134, P0138, P0140, P0336, P0337, P0501, P0502, P1133, 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 scan tool testing. Menu Read Values