Code Definition

P1186 — Engine Oil Temperature circuit performance

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

About P1186

P1186 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 P1186 is stored, the module has detected a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour.

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.

P1186 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

The engine oil temperature sensor is a negative temperature coefficient (NTC) thermistor immersed in the oil gallery or sump, and the Engine Control Module (ECM) uses its value for oil life monitoring, variable valve timing control, cooling fan strategy and in some cases fuelling and transmission shift scheduling. DTC P1186 is a rationality or performance fault rather than a hard circuit fault, and it is set when the ECM finds the oil temperature value implausible compared with the other temperature inputs it can cross check against, most commonly the engine coolant temperature and intake air ...

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

Quick Facts