What P0144 means
Sensor 3 is a third oxygen sensor on bank 1, behind a second converter or converter brick.
How the engine computer detects it
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.
Written from public technical sources and not yet checked by a mechanic. How we write these pages
Symptoms
- Check engine light on (usually after two drive cycles)
- Catalyst monitor readiness not set
- Usually no noticeable change in driving
Common causes
- Signal wire shorted to heater supply or battery voltage Most likely
- Sensor faulty internally (heater-to-signal short) Possible
- Signal circuit open or high-resistance (GM bias logic) Possible
How to diagnose P0144
- Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
- Inspect the parts involved: oxygen sensor bank1 sensor3, oxygen sensor wiring, catalytic converter.
- Work through the causes above from most to least likely, cheapest checks first.
- Clear the code and drive a full drive cycle to confirm the repair held.
Reading the code
- P
- Powertrain
- 0
- Generic (SAE) code
- 1
- Fuel and air metering
- 44
- Specific fault
Questions drivers ask
Can I drive with code P0144?
Usually yes for a short time, if the car drives normally, the temperature gauge reads normal and the check engine light is steady. If the light flashes, the engine loses power or overheats, or other warning lights come on, pull over and have it checked.
Will my car pass an emissions inspection with P0144?
Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.
Will P0144 clear by itself?
The light can go off after several drive cycles without the fault, but the code returns if the cause is still there. After a repair, the readiness monitors need a full drive cycle before an inspection.
Can I fix P0144 myself?
Often yes, with an OBD-II scanner and basic tools. Difficulty: easy. Start with the cheapest checks before replacing expensive parts.
This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.