P0145O2 Sensor Circuit Slow Response 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. P0145 means sensor 3 reacts too slowly to mixture changes, typically measured around fuel cut-off as for sensor 2 (P0139). No manufacturer document using exactly this code was found – Jaguar Land Rover, the only documented user of sensor 3, does not list it. The description rests on CARB's response-rate requirement for downstream sensors and on the sensor 2 test logic. 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)
- Usually no noticeable change in driving
- Likely causes
- LikelySensor aged or contaminated (oil ash, silicone, additives)
- PossibleExhaust leak ahead of the sensor
- PossibleSensor heater weak, sensor too cold
- 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.