Engine Coolant Temperature Sensor on Radiator, Checking

Engine Coolant Temperature Sensor on Radiator, Checking


• Cooling system is under pressure.

• Danger of scalding when opening!

• Use only gold-plated terminals when servicing terminals in the electrical harness connector of Engine Coolant Temperature (ECT) Sensor (on Radiator) (G83).

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Engine Control Module (ECM) (J623) fuses OK.

• Battery voltage at least 12.5 volts.

• All electrical consumers such as, lights and rear window defroster, switched off.

• Vehicles with automatic transmission, shift selector lever into position "P" or "N".

• A/C switched off.

• Ground connections between engine/transmission/chassis OK.

• Ignition switched off.

• Engine cold.

Test procedure

- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check.

Start diagnosis

- Disconnect the Engine Coolant Temperature (ECT) Sensor (on Radiator) (G83) electrical harness connector - 1 -.





Checking internal resistance

- Using a multimeter, check the Engine Coolant Temperature (ECT) Sensor (on Radiator) (G83) terminals 1 to 2 for resistance.





Use the chart below for the specified values:

• Area A: Resistance values 0 to 50° C.

• Area B: Resistance values 50 to 100° C.

Specified values:





• Range A, 30° C equals a resistance of 1.5 to 2.0 kohms

• Range B, 80° C equals a resistance of 275 to 375ohms

If any of the specified values were Not obtained:

- Replace the Engine Coolant Temperature (ECT) Sensor (on Radiator) (G83).

If the specified value was obtained:

Checking wiring

If the manufacturers test box is being used. Perform the following step.

- Install the test box.

If the manufacturers test box is not being used. Perform the following step.

- Remove the Engine Control Module (ECM) (J623). Refer to the Repair Information.

- Using a multimeter, check the Engine Coolant Temperature (ECT) Sensor (on Radiator) (G83) electrical harness connector terminals to the Engine Control Module (ECM) (J623) electrical harness connector T121 terminals for resistance.










Specified value: 1.5 ohms Max.

If the specification was Not obtained:

- Check the wiring for an open circuit, high resistance, a short circuit to each other, Battery (+) or Ground.

- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

- If necessary, repair the faulty wiring connection.

If the specification was obtained:

- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

- Perform a road test to verify repair.

If the DTC does not return:

Generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.

If the DTC returns, no malfunction is found in the wiring and the voltage supply not was OK:

- Replace the Engine Control Module (ECM) (J623). Refer to the Repair Information.

- Assembly is performed in the reverse of the removal.

Final procedures

After repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.