P0144O2 Sensor Circuit High Voltage Bank 1 Sensor 3
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Sensor 3 is a third oxygen sensor on bank 1, behind a second converter or converter brick. It only exists on some vehicles – documented for Jaguar Land Rover's 3.0 V6 supercharged (2013–2016, where sensor 2 is 'mid-cat' and sensor 3 'post-cat') and Ford systems that monitor part of the converter volume. P0144 means the signal of sensor 3 stays above its upper limit, usually because the heater supply or another voltage reaches the signal wire. Ford's over-voltage test (above 1.1 V for 10 s, after 90 s of heating) explicitly covers downstream sensors 2 and 3; Jaguar Land Rover lists the code for its post-cat sensor. When it fails, the control module stops the downstream trim and cannot evaluate the converter; there is no limp mode.
- What you may notice
- Check engine light on (usually after two drive cycles)
- Catalyst monitor readiness not set
- Usually no noticeable change in driving
- Likely causes
- LikelySignal wire shorted to heater supply or battery voltage
- PossibleSensor faulty internally (heater-to-signal short)
- PossibleSignal circuit open or high-resistance (GM bias logic)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €60 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.