P0157 — O2 Sensor Circuit Malfunction (Bank 2 Sensor 2)
Can drive — fix at your convenience.
What P0157 means
This code means the downstream oxygen sensor on bank 2 is sending the computer a signal that's malfunctioning or outside the expected range. Because this sensor monitors the catalytic converter rather than adjusting fuel, the effect on driving is usually minor. It's most often fixed by replacing the sensor, though wiring or connector issues can also be the cause.
Common symptoms
- Check engine light is on
- Usually little or no change in driving feel
- Possible minor decrease in fuel economy
- Failed emissions or readiness monitor test
- Occasional surging or hesitation in rare cases
Common causes
- Faulty downstream O2 sensor on bank 2
- Damaged or corroded sensor wiring or connector
- Short or open in the sensor signal circuit
- Exhaust leak near the rear sensor
- Carbon or contamination on the sensor element
Typical repair cost
$150 – $350
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0157 code?
Yes, usually. The downstream sensor mainly watches the catalytic converter, so the car typically drives normally. Still, plan to fix it before an emissions test since the light will stay on.
How much does it cost to fix a P0157 code?
Most repairs land between $150 and $350. The oxygen sensor and labor are the main costs, while a wiring or connector repair tends to be cheaper.
Is a P0157 code serious?
It's a low-severity code in most cases. It rarely affects performance, but it keeps the check engine light on and can cause an emissions failure if left unaddressed.
Does P0157 mean my catalytic converter is bad?
Not necessarily. This code points to the sensor circuit itself, not the converter. A faulty rear sensor can throw the code even when the catalytic converter is perfectly fine, so the sensor should be checked first.