P0144: O2 Sensor Circuit High Voltage (Bank 1, Sensor 3)
Quick Answer
Safe to drive (short-term)
P0144 means the third oxygen sensor on bank 1, fitted after a second (usually under-floor) catalytic converter, is reporting a voltage that stays too high for too long, above roughly 1.0V. Only a minority of cars have a Sensor 3, typically petrol engines built to the strictest emissions standards with two catalysts in series; most cars have two sensors per bank and cannot set this code.
- Severity
- Moderate · Emissions
- Estimated repair cost
- From €65 to €800+, varies by vehicle
€65 or €800, depending on your car.
- Repair shorted sensor wiring€65–€180
- Diagnose and fix rich condition (injector, fuel pressure, contamination)€110–€800
A scan shows whether P0144 is really stored on your car, which codes sit next to it and how urgent each one is.
A scan needs a Bluetooth OBD2 adapter (Bluetooth LE on iPhone), about €25-60; the built-in demo runs without one. See which adapter to buy
What does P0144 mean?
P0144 is a emissions-related diagnostic trouble code classified as moderate severity.
Where it is on the car
- Engine
- Oxygen sensor before the converter (sensor 1)
- Catalytic converter
- Oxygen sensor after the converter (sensor 2, or 3 on some cars)
- Silencer and tailpipe
What are the symptoms of P0144?
- Check engine light illuminated
- Increased fuel consumption in some cases
- Possible failed emissions test
- Usually no noticeable change in driveability
- May appear alongside catalyst codes such as P0420
What causes P0144?
Failed Bank 1 Sensor 3 stuck at high voltage
: high
Genuine rich condition reaching Sensor 3 (leaking injector, high fuel pressure)
: medium
Short to voltage in the Sensor 3 signal wire
: medium
Sensor element contamination (oil, coolant, silicone)
: medium
Failing secondary catalyst no longer storing oxygen
: low
Is it safe to drive with P0144?
Generally yes, for short-term driving. Safe to drive short term. Sensor 3 is a monitoring sensor after a second catalytic converter and does not drive fuel mixture, but persistent high voltage may signal a genuine rich condition or contamination that should be diagnosed within a few weeks.
How do you diagnose P0144?
- Confirm the vehicle's exhaust layout. Sensor 3 is only present on cars with a third oxygen sensor after a second catalytic converter
- Read freeze frame data and look for companion codes (P0172, P0175, P0420) that indicate a real rich condition or catalyst issue
- Check long-term fuel trims. Significantly negative LTFT (under -10%) suggests a genuine rich condition rather than a faulty sensor
- Inspect the Sensor 3 signal wire for shorts to voltage, especially near heat shields and chassis power runs
- Substitute a known-good sensor. If high voltage persists, the issue is upstream (fuel mixture or wiring)
How much does P0144 cost to fix?
| Repair | Parts Cost | Labor Cost | Total Estimate | DIY Difficulty |
|---|---|---|---|---|
| Replace Bank 1 Sensor 3 | €50–€220 | €60–€160 | €110–€380 | Moderate |
| Repair shorted sensor wiring | €5–€30 | €60–€150 | €65–€180 | Moderate |
| Diagnose and fix rich condition (injector, fuel pressure, contamination) | €30–€500 | €80–€300 | €110–€800 | Professional |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
Related diagnostic codes
Common questions about P0144
- Why does my car have three O2 sensors per bank?
- Some petrol cars built to the strictest emissions standards have a second catalytic converter further down the exhaust, with a third oxygen sensor after it to monitor it. Most passenger cars only have two sensors per bank.
- Can I drive with P0144?
- Yes, short term. Sensor 3 is a monitoring sensor and does not drive fuel mixture decisions. If the underlying issue is a real rich condition though, prolonged driving wastes fuel and may damage the catalyst stages over time.
- Where is Bank 1 Sensor 3 located?
- After the second catalytic converter on bank 1, usually under the car and further back along the exhaust than Sensor 2. The exact position varies by model, so confirm it in the service information before ordering a sensor.
- How do I know if the sensor or the engine is at fault?
- Check long-term fuel trims. A negative LTFT under -10% means the engine is genuinely running rich, so the sensor is reporting correctly. A normal LTFT around 0% with stuck-high Sensor 3 voltage means the sensor itself or its wiring has failed.