Toyota Tacoma manuals

Toyota Corolla Repair Manual: 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 startup. If, after sufficient time has passed, the sensor still reports that the engine is not warm enough for closedloop 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 airfuel 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

Insufficient coolant temperature for closed loop fuel control
Dtc p0125 insufficient coolant temperature for closed loop fuel control ...

Inspection procedure
Hint: if dtcs p0115, p0116, p0117, p0118 and p0125 are output simultaneously, the engine coolant temperature sensor circuit may be open or short. Perform the troubleshooting of dtc p0115, ...

Other materials:

Monitor description
The battery supplies electricity to the ecm even when the ignition switch is off. This electricity allows the ecm store data such as dtc history, freeze frame data, fuel trim values, and other data. If the battery voltage falls below a minimum level, the ecm will conclude that there is a fault ...

Circuit description
The seat belt buckle switch (lh) circuit consists of the airbag sensor assy center and front seat inner belt assy (lh). Dtc b0126/b0127/27 is recorded when a malfunction is detected in the seat belt buckle switch (lh) circuit. Wiring diagram ...

Fuel information
You must only use unleaded gasoline in your vehicle. Select octane rating 87 (Research Octane Number 91) or higher. Use of unleaded gasoline with an octane rating lower than 87 may result in engine knocking. Persistent knocking can lead to engine damage. At minimum, the gasoline you use should ...

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