Chevrolet OBD codes
Search Chevrolet fault-code guides when you want the generic OBD-II definition with notes that are a little closer to common Chevrolet fault patterns.
Showing 4 sample guides. Refresh to rotate the mix.
P0420
P0420 usually means the catalytic converter efficiency is below the threshold the ECU expects.
On many Chevrolet vehicles, exhaust leaks, sensor bias, or a tired catalytic converter can sit behind P0420.
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P0300
P0300 usually means the engine is detecting random or multiple-cylinder misfires.
On many Chevrolet vehicles, ignition weakness, intake leaks, or fuel-delivery problems are common starting points for P0300.
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P0171
P0171 usually means bank 1 is running too lean.
On many Chevrolet vehicles, unmetered air and airflow-sensor bias are common first checks for P0171.
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P0174
P0174 usually means bank 2 is running too lean.
A vacuum leak, airflow sensor issue, or fuel-delivery problem is the first place to look.
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