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
P0391
Camshaft Position Sensor B Circuit Range/Performance Bank 2
Generic
Ignition System
High severity
P0395
Cylinder pressure sensor, cylinder 1 circuit malfunction
Generic
Ignition System
High severity
P0401
Exhaust Gas Recirculation Flow Insufficient Detected
Generic
Auxiliary Emissions Control
Medium severity
P0404
Exhaust Gas Recirculation Circuit Range/Performance
Generic
Auxiliary Emissions Control
Medium severity
P0408
Exhaust Gas Recirculation Sensor B Circuit High
Generic
Auxiliary Emissions Control
Medium severity
P0411
Secondary Air Injection System Incorrect Flow Detected
Generic
Auxiliary Emissions Control
Medium severity
P0414
Secondary Air Injection System Switching Valve A Circuit Shorted
Generic
Auxiliary Emissions Control
Medium severity
P0417
Secondary Air Injection System Switching Valve B Circuit Shorted
Generic
Auxiliary Emissions Control
Medium severity
P0421
Warm Up Catalyst Efficiency Below Threshold Bank 1
Generic
Auxiliary Emissions Control
Medium severity
P0424
Heated Catalyst Temperature Below Threshold Bank 1
Generic
Auxiliary Emissions Control
Medium severity
P0426
Catalyst Temperature Sensor Range/Performance Bank 1 Sensor 1
Generic
Auxiliary Emissions Control
Medium severity
P0428
Catalyst Temperature Sensor High Input Bank 1 Sensor 1
Generic
Auxiliary Emissions Control
Medium severity
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