All codes › P0172

P0172 — Fuel System Too Rich (Bank 1)

P0172 is set when the engine control module detects that long-term fuel trim on Bank 1 has been driven beyond approximately −25 % — the ECM is pulling out the maximum amount of fuel it is allowed to remove, and the oxygen sensor still reports a rich mixture. The cause is something delivering excess fuel or restricting air, or a sensor reporting a false rich signal.

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