What does it mean?
P1168 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Lean A/F Sensor (Bank 1 Sensor 1) Label Circuit Low Input .
Symptoms
- Check engine light on with the code stored
- Fuel trims drift and the engine may run rich or lean without an obvious mechanical cause
- Slightly rough idle and reduced throttle response
- Higher fuel consumption
- Closed loop control may be suspended, leaving the engine on a fixed fuelling map
Likely causes
- Calibration resistor inside the sensor has failed or drifted low
- Short to ground in the label or calibration wire, often where the harness rubs on the exhaust or a bracket
- Incorrect replacement sensor whose calibration value does not match the module
- Moisture or corrosion inside the sensor connector bridging pins
- Damaged or bent terminal in the connector giving a false low reading
- Rarely, a control module input circuit fault
How to fix it
- Read freeze frame and check whether the fault is permanent or appears only over bumps
- Unplug the sensor and measure the calibration circuit voltage at the harness side with the ignition on
- Check the calibration wire for a short to ground by measuring resistance to chassis with the module disconnected
- Inspect the connector for water, corrosion, or a terminal pushed back in its housing
- Confirm the fitted sensor is the correct part for the engine; a mismatched calibration resistor sets this code
- Repair or replace the damaged harness section, then clear the code and road test
- Replace the sensor if its internal calibration resistance is out of specification