Toyota Corolla (E120): Circuit description

Refer to dtc p0115

Dtc no.

Dtc detection condition

Trouble area

P0125 If the engine coolant temperature (ect) was less than –6.6 °C (20 °F) when starting the engine, and 20 minutes after the engine start, the ect sensor still indicates below 20 °C (68 °F)
  • Cooling system
  • engine coolant temperature sensor
  • thermostat
If the ect was between –6.6 °C (20 °F) and 10 °C (50 °F) when start, 5 minutes after the start, the ect sensor still indicates below 20 °C (68 °F)
If the ect was greater than 10 °C (50 °F) when starting the engine, and 2 minutes after the engine start, ect sensor still indicates below 20 °C (68 °F)

Monitor description

The engine coolant temperature (ect) sensor is used to monitor the temperature of the engine coolant. The resistance of the sensor varies with the actual coolant temperature. The ecm applies a voltage to the sensor and the varying resistance of the sensor causes the signal voltage to vary. The ecm monitors the ect signal voltage after engine start–up. If, after sufficient time has passed, the sensor still reports that the engine is not warm enough for closed–loop fuel control, the ecm interprets this as a fault in the sensor or cooling system.

Example: the engine coolant temperature was 0 c (32 f) at engine start. After 5 minutes running time, the coolant temperature sensor still indicates that the engine is not warm enough to begin air–fuel ratio feedback control.

The ecm interprets this as a fault in the sensor or cooling system and will set a dtc.

Monitor strategy

Typical enabling conditions

Typical enabling conditions

Typical malfunction thresholds

Typical malfunction thresholds

Wiring diagram

Wiring diagram

Refer to dtc p0115

    Share this page:

    Other materials:

    Floor shift cable transmission control shift
    Replacement Hint: components: 1. Remove air conditioner unit assy Hint: refer to the instructions for removal of the air conditioner unit assy. 2. Separate air bag sensor assy center  remove the 3 bolts, separate the airbag sensor assy center. 3. Remove exhaust pipe assy 4. Remo ...

    Starting the engine
    1 Continuously variable transmission: Ensure that the shift lever is in P and depress the brake pedal. Manual transmission: Shift the shift lever to N and depress the clutch pedal. 2 Touch the Toyota emblem side of the electronic key to the engine switch. When the electronic key is detected, a ...

    Replacement
    1. Remove console box sub–assy rear 2. Remove parking brake lever sub–assy Disconnect the parking brake switch connector from the parking brake switch.  remove the lock nut and adjusting nut from the parking brake cable assy no.1. Remove the 2 bolts. Usin ...