Code Definition

P1116 — Engine Coolant Temperature Erratic

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

About P1116

P1116 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.

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.

P1116 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 coolant temperature sensor is a negative temperature coefficient thermistor sitting in the coolant jacket, fed with a 5V reference through a pull up resistor inside the Powertrain Control Module, so its signal voltage falls smoothly as coolant temperature rises, running from around 4.5V on a cold engine to under 1.0V at full operating temperature. Because coolant represents a large thermal mass, the module knows genuine temperature change must be gradual, so it monitors the rate at which the reading moves as well as its absolute value. GM DTC P1116 sets when the coolant temperature ...

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