Code Definition

P1136 — 5 Volt Reference 2 Circuit, or O2 Sensor Bank 1 Sensor 1 Reading Rich

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

About P1136

P1136 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 P1136 is stored, the module has detected 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.

P1136 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 carries two platform dependent definitions, a fault on the number 2 five volt reference circuit, or the Bank 1 upstream oxygen sensor reading persistently rich. The 5V Reference 2 circuit is one of the regulated reference buses the PCM supplies to a group of sensors, and the code flags when that reference is out of range, often biased high or otherwise faulty. In the oxygen sensor form, P1136 is the rich counterpart to P1135, setting when the Bank 1 Sensor 1 signal stays high in voltage and biased rich, failing to swing lean during closed loop operation. Depen...

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