What does it mean?
P1161 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Intake Air Temperature (IAT) Sensor -G72-Open circuit/short circuit to B+ .
Symptoms
- Malfunction indicator lamp on with intake air temperature shown as extremely low or fixed at a limit value
- Hard starting and a rich mixture, especially in warm weather
- Rough idle and hesitation under light acceleration
- Increased fuel consumption and a sooty exhaust tip
- Reduced power and a general lack of throttle sharpness
Likely causes
- Broken signal or ground wire between the sensor and the PCM (powertrain control module)
- Connector unplugged, not fully latched or with a terminal backed out
- Open circuit inside the sensor element after age or vibration damage
- Signal wire shorted to battery voltage or to another powered circuit in the same loom
- Corroded terminals adding enough resistance to look like an open circuit
- Harness damage from rodents or from an intake component being removed and refitted
- Poor sensor ground at the module side, raising the signal to reference level
How to fix it
- Look at the intake air temperature value in live data and note whether it sits at a fixed limit
- Jumper the sensor signal wire to ground at the connector with the key on; a reading that swings to the opposite extreme proves the wiring and module are good and the sensor is open
- Measure resistance across the sensor pins and compare with the temperature and resistance table
- Check continuity of the signal and ground wires from the sensor connector to the module
- Test the signal wire for voltage with the sensor disconnected to find a short to power
- Inspect the connector for backed-out terminals, corrosion and a broken lock tab
- Repair the open or shorted circuit, or replace the sensor, then confirm the reading matches ambient temperature on a cold engine