What does code P1131 mean?

Q: What does code P1131 mean?

HO2S Circuit Low Variance Bank 1 Sensor 2. P1131 on a GM vehicle means the powertrain control module has detected that the downstream heated oxygen sensor (HO2S) on bank 1 is not switching voltage as it should, staying too close to a fixed value instead of oscillating normally. The computer is watching for low variance in the sensor signal, which tells it the sensor is lazy, contaminated, or the circuit has a problem.

DTC codes / GM codes / P1131

P1131 · GMHO2S Circuit Low Variance Bank 1 Sensor 2

P1131 on a GM vehicle means the powertrain control module has detected that the downstream heated oxygen sensor (HO2S) on bank 1 is not switching voltage as it should, staying too close to a fixed value instead of oscillating normally. The computer is watching for low variance in the sensor signal, which tells it the sensor is lazy, contaminated, or the circuit has a problem.

SystemPowertrain

Code typeGM specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Guidance is general and written for GM vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.