DTC P1172: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Circuit Out of Range High: General Description

If a malfunction causes the air/fuel sensor value sent to the engine control module (ECM)/powertrain control module (PCM) to deviate from the normal control area, the air/fuel (A/F) sensor may still become active after the engine starts, but the air/fuel feedback does not start normally and the emissions deteriorate. When the A/F sensor output is out of the normal area, and this condition continues after the A/F sensor is active, the ECM/PCM detects a malfunction and a DTC is stored.