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
P1421
Secondary Air Injection Valve Circuit Short To Ground
Audi
Auxiliary Emissions Control
Medium severity
P1423
Bank 1 Secondary Air Injection System Output Too Small
Audi
Auxiliary Emissions Control
Medium severity
P1427
Brake System Vacuum Pump Activation Short To Positive
Audi
Vehicle Speed and Idle Control System
Low severity
P1428
Brake System Vacuum Pump Activation Short To Ground
Audi
Vehicle Speed and Idle Control System
Low severity
P1445
Catalyst Temperature Sensor 2 Circuit Range/Performance
Audi
Auxiliary Emissions Control
Medium severity
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