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:

    Instrument panel
    Engine switch Starting the engine/changing the positions*1 Starting the engine/changing the modes*2 Emergency stop of the engine When the engine will not start Warning messages Shift lever Changing the shift position Precautions for towing When the shift lever does not move Meters Read ...

    Emergency flashers
    The emergency flashers are used to warn other drivers when the vehicle has to be stopped in the road due to a breakdown, etc. Press the switch. All the turn signal lights will flash. To turn them off, press the switch once again. ■Emergency flashers If the emergency flashers are used ...

    Cd sound skips
    Inspection procedure 1 Disc cleaning Disk cleaning ) if the disk gets dirty, clean the disk by wiping the surface from the center to outside in the radial directions with a soft cloth. Notice: do not use a conventional record cleaner or anti–static preservative. Standard: ...