Code Definition

P1154 — O2 Sensor Low Transition Time (Bank 2 Sensor 1)

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: GM

About P1154

P1154 is a manufacturer-specific powertrain diagnostic trouble code recorded for GM vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1154 is stored, the module has detected a signal or supply voltage lower than the expected operating range; a bank-specific fault, meaning it applies only to one cylinder bank of a multi-bank engine; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1154 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

This General Motors specific code relates to the response timing of the Bank 2 Sensor 1 upstream oxygen sensor. As part of monitoring sensor health, the PCM times how the sensor transitions between its rich and lean states and compares that against expected limits. P1154 sets when the measured transition time on Bank 2 Sensor 1 falls outside the normal window, indicating the sensor is not behaving the way a correctly responding sensor should during the rationality test. This usually reflects a contaminated or biased sensor, a skewed mixture on that bank, or an exhaust leak influencing the read...

Join TaT to view the complete code information and diagnostic details.

Quick Facts