OBD fault code library
Look up any P or U code to see what it means, what causes it, the parts involved and how it gets fixed.
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Fault codes
P0423
Heated Catalyst Efficiency Below Threshold Bank 1
Generic
Auxiliary Emissions Control
Medium severity
P0425
Catalyst Temperature Sensor Circuit Bank 1 Sensor 1
Generic
Auxiliary Emissions Control
Medium severity
P0427
Catalyst Temperature Sensor Low Input Bank 1 Sensor 1
Generic
Auxiliary Emissions Control
Medium severity
P0430
Catalyst System Efficiency Below Threshold Bank 2
Generic
Auxiliary Emissions Control
Medium severity
P0431
Warm Up Catalyst Efficiency Below Threshold Bank 2
Generic
Auxiliary Emissions Control
Medium severity
P0433
Heated Catalyst Efficiency Below Threshold Bank 2
Generic
Auxiliary Emissions Control
Medium severity
P0434
Heated Catalyst Temperature Below Threshold Bank 2
Generic
Auxiliary Emissions Control
Medium severity
P0436
Catalyst Temperature Sensor Range/Performance Bank 2 Sensor 1
Generic
Auxiliary Emissions Control
Medium severity
P0437
Catalyst Temperature Sensor Low Input Bank 2 Sensor 1
Generic
Auxiliary Emissions Control
Medium severity
P0440
Evaporative Emission Control System Malfunction
Generic
Auxiliary Emissions Control
Low severity
P0442
Evaporative Emission Control System Leak Detected Small Leak
Generic
Auxiliary Emissions Control
Low severity
P0443
Evaporative Emission Control System Purge Control Valve Circuit Malfunction
Generic
Auxiliary Emissions Control
Low severity
P0445
Evaporative Emission Control System Purge Control Valve Circuit Shorted
Generic
Auxiliary Emissions Control
Low severity
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