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DTC - Diagnostic Trouble Codes information

P0125

Powertrain Codes

P0125 - LEXUS - Insufficient Coolant Temperature for Closed Loop Fuel Control

Symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

Possible Causes

- Low engine coolant level - Engine Coolant Temperature (ECT) sensor harness is open or shorted - Engine Coolant Temperature (ECT) sensor electrical circuit poor connection - Faulty Engine Coolant Temperature (ECT) sensor - Faulty engine coolant thermostat

When Detected

The voltage sent to Engine Control Module (ECM) from the sensor is not practical, even when some time has passed after starting the engine.

Description

The Engine Coolant Temperature (ECT) sensor is used to detect the engine coolant temperature. The sensor modifies a voltage signal from the Engine Control Module (ECM). The modified signal returns to the ECM as the engine coolant temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.