P1172

DTC P1172: A/F Sensor (Sensor 1) Circuit Out of Range Low

1. Reset the ECM/PCM.
2. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
3. Check for Temporary DTCs or DTCs with the HDS or a scan tool.

Are any Temporary DTCs or DTCs indicated?

YES - Replace the A/F sensor (Sensor 1).

NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the A/F sensor (Sensor 1), the A/F sensor relay, and the ECM/PCM.