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
P1420
NOx Adsorptive Catalyst System Efficiency Below Threshold
Honda
Auxiliary Emissions Control
High severity
P1421
Intake Air Low Pressure Switch Circuit High Voltage
Honda
Auxiliary Emissions Control
Medium severity
P1423
Intake Air High Pressure Switch Circuit High Voltage
Honda
Auxiliary Emissions Control
Medium severity
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