What does it mean?
P1164 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Air Fuel Sensor (Bank 1 Sensor 1) Range/Performance .
Symptoms
- Check engine light on
- Rough idle, mild surging or hesitation under light load
- Fuel trims far from zero on bank 1 while bank 2 looks normal
- Poor fuel economy and reduced throttle response
- Occasional black smoke or fuel smell at idle
- Emissions test failure
Likely causes
- Drifted or contaminated sensing element giving a plausible but wrong reading
- Incorrect or low-quality replacement sensor whose calibration does not match the control module
- Exhaust leak upstream of the sensor skewing the oxygen measurement
- Intake or vacuum leak, or a fuel pressure fault, that shifts the real mixture away from the commanded value
- Heater circuit that warms the element too slowly, so readings stay biased
- High resistance in the sensor signal or ground wiring, corroded connector terminals
- Rarely, a control module calibration or drive circuit problem
How to fix it
- Record freeze frame data and read short and long term fuel trims for both banks
- Watch the sensor's live value during idle, steady cruise and deceleration; a healthy sensor swings clearly with commanded mixture changes
- Force a rich and a lean condition and confirm the sensor follows
- Inspect the exhaust ahead of the sensor and the sensor bung for leaks
- Check connector pins, sensor ground and signal wire resistance with a multimeter
- Verify fuel pressure, injector condition and the intake for unmetered air
- Fit the correct original-specification sensor if it fails the response check, then clear codes and re-verify trims