3. Turn ignition switch ON.
4. Set selector lever to D position (A/T), 1st position (M/T)
5. Check voltage between ECM terminals 22 (TP sensor 1 signal), 23 (TP sensor 2 signal) and ground under

the following conditions.

6. If NG, replace electric throttle control actuator and go to the next step.
7. Perform

EC-591, "Throttle Valve Closed Position Learning"

8. Perform

EC-591, "Idle Air Volume Learning"

Terminal

Accelerator pedal

Voltage

22
(Throttle position sensor 1)

Fully released

More than 0.36V

Fully depressed

Less than 4.75V

23
(Throttle position sensor 2)

Fully released

Less than 4.75V

Fully depressed

More than 0.36V

P0125 ECT SENSOR

EC-657

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

P0125 ECT SENSOR

Component Description

INFOID:0000000009481308

The engine coolant temperature sensor is used to detect the engine

coolant temperature. The sensor modifies a voltage signal from the

ECM. The modified signal returns to the ECM as the engine coolant

temperature input. The sensor uses a thermistor which is sensitive to

the change in temperature. The electrical resistance of the ther-

mistor decreases as temperature increases.

<Reference data>

*: This data is reference value and is measured between ECM terminal 70 (Engine
coolant temperature sensor) and ground.

CAUTION:

Never use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-

age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

On Board Diagnosis Logic

INFOID:0000000009481309

NOTE:

If DTC P0125 is displayed with P0116, first perform the trouble diagnosis for DTC P0116. Refer to

EC-

647, "Component Description"

NOTE:

If DTC P0125 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117 or

P0118. Refer to

EC-650, "Component Description"

DTC Confirmation Procedure

INFOID:0000000009481310

CAUTION:

Never overheat engine.

NOTE:

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-

ing the next step.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.

WITH CONSULT

SEF594K

Engine coolant temperature [

°C (°F)]

Voltage* (V)

Resistance (k

Ω)

-10 (14)

4.4

7.0 - 11.4

20 (68)

3.5

2.1 - 2.9

50 (122)

2.2

0.68 - 1.00

90 (194)

0.9

0.236 - 0.260

SEF012P

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0125
0125

Insufficient engine cool-
ant temperature for
closed loop fuel control

• Voltage sent to ECM from the sensor is not

practical, even when some time has passed
after starting the engine.

• Engine coolant temperature is insufficient for

closed loop fuel control.

• Harness or connectors

(High resistance in the circuit)

• Engine coolant temperature sensor
• Thermostat

EC-658

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

P0125 ECT SENSOR

1. Turn ignition switch ON.

2. Select “DATA MONITOR” mode with CONSULT.

3. Check that “COOLAN TEMP/S” is above –10

°C (14°F).

If the temperature is above –10

°C (14°F), the test result will be OK.

If the temperature is below –10

°C (14°F), go to following step.

4. Start engine and run it for 65 minutes at idle speed.

If “COOLAN TEMP/S” increases to more than –10

°C (14°F) within 65 minutes, stop engine because

the test result will be OK.

5. Check 1st trip DTC.

6. If 1st trip DTC is detected, go to

EC-658, "Diagnosis Procedure"

WITH GST

Follow the procedure “WITH CONSULT” above.

Diagnosis Procedure

INFOID:0000000009481311

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

2. Loosen and retighten three ground screws on the body. Refer to

EC-617, "Ground Inspection"

OK or NG

>> GO TO 2.

>> Repair or replace ground connections.

CHECK ENGINE COOLANT TEMPERATURE SENSOR

Refer to

EC-658, "Component Inspection"

OK or NG

>> GO TO 3.

>> Replace engine coolant temperature sensor. Refer to

CO-57, "Exploded View"

CHECK THERMOSTAT OPERATION

When the engine is cold [lower than 70

°C (158°F)] condition, grasp lower radiator hose and confirm that the

engine coolant does not flow.
OK or NG

>> GO TO 4.

>> Repair or replace thermostat. Refer to

CO-55, "Removal and Installation"

CHECK INTERMITTENT INCIDENT

Refer to

GI-42, "Intermittent Incident"

>> INSPECTION END

Component Inspection

INFOID:0000000009481312

ENGINE COOLANT TEMPERATURE SENSOR

1. Check resistance between engine coolant temperature sensor

terminals 1 and 2 as shown in the figure.

JMBIA0080ZZ

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