What does it mean?
P1167 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Air Fuel Sensor (Bank 1 Sensor 1) Heater Circuit Malfunction .
Symptoms
- Check engine light on shortly after a cold start
- Extended open loop operation with a rich, fuel-heavy warm-up
- Slight stumble at idle while the engine is cold
- Increased fuel consumption on short trips
- Readiness monitors stay incomplete, so the vehicle cannot pass an emissions check
Likely causes
- Open heater winding inside the sensor after long service or thermal shock from water splash
- Damaged heater supply wire: chafed against the exhaust, pinched under a bracket or broken at a repair splice
- Corroded, pushed-out or overheated terminal in the sensor connector
- Fuse, relay or shared supply feeding several heater circuits has failed
- Weak or corroded module ground affecting the heater driver reference
- Failed heater driver in the control module
How to fix it
- Read all stored codes; if several heater codes are present, suspect a shared fuse, relay or ground
- Measure heater element resistance at the sensor connector and compare with specification
- Confirm battery voltage on the supply pin with the ignition on
- Check the control wire for continuity back to the module and for a short to ground or voltage
- Inspect the harness along the exhaust and under heat shields for melted or brittle insulation
- Repair or reroute damaged wiring and clean corroded terminals
- Replace the sensor only when the element is proven open or shorted, then verify the heater monitor runs