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:

    Rear seats
    The seatbacks of the rear seats can be folded down. Folding down the rear seatbacks 1. Move the front seats forward. 2. Stow the rear armrest. (if equipped). 3. Fold the seatback down while pushing the seatback lock release button. Each seatback may be folded separately. WARNING Observe the follo ...

    Safety Connect
    *: If equipped Safety Connect is a subscription- based telematics service that uses Global Positioning System (GPS) data and embedded cellular technology to provide safety and security features to subscribers. Safety Connect is supported by Toyota's designated response center, which operates 24 hour ...

    Circuit description
    Refer to dtcs p0100 Dtc no. Dtc detection condition Trouble area P0101 After engine is warmed up, conditions (a) to (d) continue for more than 10 seconds (2 trip detection logic):  engine speed less than 900 rpm  throttle valve fully closed &nbs ...