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P0420

Read the instructions below then start the fault diagnostic procedure.

Symptom: Market US/CA: CHECK ENGINE

P0420


Three Way Catalytic Converter. Malfunction.


Fault symptoms


Market US/CA: 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°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°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 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, 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, see .)


- 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, see .