P0144 — O2 Sensor Circuit High Voltage (Bank 1 Sensor 3)
Can drive — fix at your convenience.
What P0144 means
This code means the rear-most oxygen sensor on Bank 1 (Sensor 3) is reporting a high voltage, which the computer reads as a constant rich condition or a circuit fault. The usual causes are a worn or contaminated sensor, damaged wiring, a corroded connector, or an internal sensor short, and occasionally a genuinely rich-running engine. The most common fix is replacing the oxygen sensor or repairing its wiring.
Common symptoms
- Check engine light is on
- Slightly reduced fuel economy
- Failed emissions or smog test
- Normal driving with no obvious power loss
- Possible faint fuel smell from the exhaust
Common causes
- Aging or contaminated rear oxygen sensor
- Internal sensor short causing high voltage
- Damaged or chafed sensor wiring
- Corroded or loose connector
- Less often, a rich-running engine condition
Typical repair cost
$150 – $400
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0144 code?
Generally yes, for the short term. This rear sensor handles emissions monitoring rather than engine control, so the car should run normally. Have it diagnosed within a week or two, and expect a failed emissions test until it's repaired.
How much does it cost to fix a P0144 code?
Most repairs land between $150 and $400. The oxygen sensor is the biggest part of the cost, with labor depending on the sensor's location. If the fault is just wiring or a connector, you may pay less.
Is a P0144 code serious?
No, it's usually low-severity. The engine isn't at risk and the car drives normally, but it does affect emissions monitoring and can slightly lower fuel economy. It's worth fixing promptly so the car can pass inspection and the code doesn't mask another exhaust issue.
Why does P0144 show high voltage?
The rear oxygen sensor's voltage rises when it senses little oxygen in the exhaust, which the computer treats as a rich condition. A reading stuck high usually means the sensor is failing or has an internal short, though wiring problems can mimic it. A scan tool checking the sensor's live data confirms whether the sensor itself is the cause.