P0420
Read the instructions below then
start the fault diagnostic procedure.
Symptom: CHECK ENGINE lamp on.
Three Way Catalytic Converter. Malfunction.
Fault symptoms
CHECK ENGINE lamp on.
Conditions
Diagnosis not yet performed during this trip
Catalytic converter heating:
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Engine speed (rpm) x load (kPa) = >60 000
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Total acceleration >15 sec.
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Above conditions fulfilled for 120 sec.
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Evaluation of catalytic converter
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Engine speed (rpm) x load (kPa) = 60 000 - 120 000
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Engine coolant temperature >60C (>140F)
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Oxygen sensor 2 >0.4 V on some occasion during this driving cycle
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Voltage changes from oxygen sensor 2 are corrected with respect to load and engine speed and are totalled in a measuring window determined by oxygen sensor 1. If the total exceeds a calibrated value, the fault criteria will have been fulfilled.
Diagnostic help
The capacity of the catalyst can be reduced temporarily or permanently for the following reasons:
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lead or sulphur in the fuel.
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additives in the engine oil when oil consumption is abnormal
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. Intermittent faults may occur in connection with short circuits and open circuits. Jiggle the wiring harness at several points and in several directions to locate any problems in the wiring, including intermediate connectors. Observe the multimeter, scan tool or test lamp during the check.
