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:

Inspection procedure
Hint: read freeze frame data using the hand-held tester or the obd ii scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the ...

Mechanical system tests
1. Perform mechanical system tests Measure the stall speed. The object of this test is to check the overall performance of the transaxle and engine by measuring the stall speeds in the d and r positions. Notice: Do the test at normal operating atf temperature 50 to 80 c (122 to ...

Initialization
1. Reset memory Caution: perform the reset memory (at initialization) when replacing the automatic transaxle assy, engine assy or ecm. Notice: handheld tester only Turn the ignition switch off.  connect the handheld tester to the dlc3.  turn the ignition switch to the on ...

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