P0145 — O2 Sensor Circuit High Voltage (Bank 1 Sensor 3)
Can drive — fix at your convenience.
What P0145 means
This code means the engine computer detected an unusually high voltage signal from the third oxygen sensor on bank 1, which monitors exhaust after the catalytic converter. It usually points to a failing O2 sensor, a wiring or connector problem, or rarely an exhaust leak affecting the reading. It's a common, sensor-related code that's typically fixable without major engine work.
Common symptoms
- Check engine light is on
- Slightly reduced fuel economy
- Failed emissions or smog test
- Occasional rough running, but often no noticeable change
- Stored O2 sensor trouble code on a scan tool
Common causes
- Failing or worn-out oxygen sensor (Bank 1 Sensor 3)
- Damaged or corroded wiring to the O2 sensor
- Loose or corroded sensor connector
- Exhaust leak near the sensor affecting readings
- Less commonly, a fault in the engine control module
Typical repair cost
$150 – $400
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0145 code?
For everyday driving, usually yes. This is an emissions sensor code, so the car should still run and won't leave you stranded. Just don't put it off for weeks, since it can hurt fuel economy and emissions over time.
How much does it cost to fix a P0145 code?
Most repairs run between $150 and $400, with the oxygen sensor itself being the main cost. If it turns out to be a wiring or connector issue, it can be cheaper, but hard-to-reach sensors raise labor.
Is a P0145 code serious?
It's generally a low-severity code. It won't damage your engine in the short term, but leaving it unfixed can mean worse mileage and a failed emissions test, so it's worth addressing soon.
What does Bank 1 Sensor 3 mean for this code?
Bank 1 Sensor 3 is an oxygen sensor mounted in the exhaust after the catalytic converter on the engine's bank 1 side. It checks how well the converter is cleaning exhaust, so a high-voltage signal here usually points to that specific sensor or its wiring.