Code Definition

P0117 — Engine Coolant Temperature Circuit Low Input

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0117

P0117 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0117 is stored, the module has detected a signal or supply voltage lower than the expected operating range.

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.

Because P0117 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The engine coolant temperature sensor is a negative temperature coefficient thermistor whose resistance falls as coolant temperature rises, with the ECM reading the resulting voltage across a pull up resistor. P0117 sets when signal voltage falls below the lower threshold for a calibrated period, corresponding to very low circuit resistance and therefore an implausibly hot indicated coolant temperature, commonly pinned at the top of the scale near 140 degrees Celsius. The realistic causes are a signal circuit shorted to ground, a sensor that has failed internally short, or contamination bridgi...

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