LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2007 >> RX 400h FWD >> Repair and Diagnosis >> Engine Performance >> Engine Control System >> SFI System >> DTC P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control >> Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control: Description

A thermistor is built into the Engine Coolant Temperature (ECT) sensor, of which the resistance value varies according to the ECT.

The structure of the sensor and its connection to the ECM (Included in HV control ECU) are the same as those of the Intake Air Temperature (IAT) sensor.

DTC DETECTION CONDITION CHART

DTC No. DTC Detection Condition Trouble Area
P0125 Engine coolant temperature (ECT) does not reach closed-loop enabling temperature for 20 minutes (this period varies with ECT when engine start)
(2 trip detection logic)
  • Engine coolant temperature sensor
  • Cooling system
  • Thermostat