Code Definition

P0115 — Engine Coolant Temperature Circuit

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

About P0115

P0115 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 P0115 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

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 P0115 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 threaded into the cylinder head, thermostat housing, or coolant outlet, with resistance falling as coolant temperature rises. The ECM reads the resulting voltage across a pull up resistor and uses the value to control cold start enrichment, fuel trim, ignition timing, cooling fan operation, closed loop entry, transmission shift strategy, and on many vehicles the temperature gauge. P0115 sets when the ECM detects the coolant temperature signal outside its acceptable operating range, a definition covering both...

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