P0420
Read the instructions below then
start the fault diagnostic procedure.
Symptom: CHECK ENGINE.
Three Way Catalytic Converter. Malfunction.
Fault symptoms
On-Board Diagnostics
Type of diagnosis:
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Once per driving cycle. Interrupted when fault criteria fulfilled or OK reported. Restarts next driving cycle.
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Enable criteria:
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General conditions for this trouble code: When starting the engine, the atmospheric pressure must exceed 78 kPa and the engine coolant and intake air temperatures must exceed -7°C.
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Ignition of catalytic converter: Engine running. Air mass flow has exceeded 6 g/s for 120 sec accumulated time. Air mass flow has exceeded 24 g/s for 18 sec accumulated time. No engine braking with fuel shut-off longer than 10 sec. No idling period longer than 40 sec.
Evaluation of three way catalytic converter: More than 200 sec since start. Coolant temperature above 70°C. Speed 40-115 km/h. Accelerator pedal depressed. Engine speed 1100-2300 rpm. Engine load 90-130 mg/c. Voltage transitions in oxygen sensor 2 are corrected with regards to load and engine speed and are accumulated during approved voltage periods for oxygen sensor 1*). When the voltage transitions have been corrected and accumulated for 20 sec the mean value of these is calculated.
*) Accepted periods have 30-80 % pulse ratio (+trigger).
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Fault criteria:
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Mean value of voltage transitions exceeding a calibrated value.
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Dependents:
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P0100, P0102, P0103, P0116, P0117, P0118, P0131, P0132, P0134, P0138, P0140, P0336, P0337, P0501, P0502, All throttle faults.
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System reaction to a fault:
OK report:
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Diagnosis performed once and fault criteria not fulfilled.
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Fault handling:
(See section
Fault handling III, other emission-related components and functions
for more information.)
Diagnostic help
The capacity of the catalytic converter can be reduced temporarily or permanently for the following reasons:
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Lead or sulphur in the fuel.
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Functions in the diagnostic tool related to the fault:
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Diagnostic status for the diagnosis.
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See also description of readings under
"Read Values" menu
for more information.
