What does code P1197 mean?

P1197 · GMO2 Sensor 1/2 (Bank 1 Sensor 2) Slow During Catalyst Monitor

P1197 on a GM vehicle means the powertrain control module (PCM) has detected that the downstream oxygen sensor on bank 1, sensor 2, is responding too slowly during the catalyst monitor test. The PCM commands a rich-to-lean fuel transition and watches how quickly the sensor voltage swings; if the response lags beyond the calibrated window, it stores this code.

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.