P0142O2 Sensor Circuit 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. P0142 is the general circuit code of this sensor. Jaguar Land Rover lists it with P0143, P0144 and P0147 for the post-cat sensor and names software (fixed by reconfiguring the engine module) and water-induced thermal shock as causes. No published thresholds exist for sensor 3; the logic follows the sensor 2 checks (P0136). 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
- LikelySensor 3 faulty (thermal shock, ageing)
- PossibleWiring or connector under the car damaged or corroded
- PossibleEngine module software (Jaguar Land Rover)
- RareExhaust leak ahead of sensor 3
- 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.