OBD codes / P0144
P0144
ModerateO2 Sensor Circuit High Voltage (Bank 1, Sensor 3)
You can drive normally with P0144 — this rearmost sensor has no role in engine control. Its jobs are emissions verification and catalyst monitoring, so schedule the repair around inspection deadlines rather than urgency.
What this code means
P0144 is the stuck-high-voltage fault for the third oxygen sensor on Bank 1 — a sensor fitted only to vehicles that run two catalytic converters in series, where it sits after the second converter as the final emissions monitor. A persistently high signal means the sensor is reporting rich nonstop, which at this point in the exhaust is rarely true. The realistic causes are a failing sensor, a wiring short to voltage (a chafed harness contacting a power wire — plausible on a long underbody run), or a contaminated sensor element. A severely rich-running engine could contribute, but that would normally set upstream codes first. As with all post-catalyst sensors, the engine runs normally; the fault matters for emissions testing and for trusting the catalyst monitor.
Symptoms you might notice
- Check-engine light, usually the sole symptom
- No change in drivability or fuel economy
- Failed emissions test
What it costs to fix
Typical range: $100–$450 · about ~0.3–1 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Oxygen (O2) sensor (post-catalyst, sensor 3) | $30–$250 | ~0.3–1 hrs |
| Wiring / connector repair | $10–$120 | ~0.5–1.5 hrs |
Typically a short, accessible under-car job. The long harness run to this rearmost sensor makes wiring inspection worthwhile before spending on a part — a short to voltage produces exactly this code and costs little to repair.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0144 for my exact vehicle →
Frequently asked
Can I keep driving with P0144?
Yes — there is no mechanical consequence to driving with a faulty third O2 sensor. It becomes a problem only at emissions-test time, when any active check-engine light means a fail.
What makes an O2 sensor read stuck high?
Either a rich signal it genuinely sees — unlikely this far downstream of two converters — or an electrical fault: an internally failed sensor, a signal wire shorted to a voltage source, or contamination on the element. Electrical causes dominate for this position.
Not all cars have this sensor, right?
Correct. Sensor 3 exists only on vehicles with two catalytic converters in line on Bank 1. If your car set P0144, it has one; a scan tool listing for your model confirms where it sits.
Should I replace all my O2 sensors at once?
The code only requires the faulty one. On a high-mileage vehicle some owners refresh same-age sensors together to save future labor, but that is optional — and pointless if the actual fault turns out to be wiring.
Seeing P0144 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0144 for my vehicleRelated trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0144 from your phone — see our honest guide to the best OBD2 Bluetooth adapters.
Generic OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.