Engine Coolant Temperature Sensor On Radiator, Checking

Special tools and workshop equipment 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 .

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

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.

Engine Coolant Temperature (ECT) Sensor (on Radiator) -G83- electrical harness connector terminals	Engine Control Module (ECM) -J623- electrical connector 121 terminals or test box socket
1	17
2	50

Specified value: 1.5 Ω 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 .

-- Perform a road test to verify repair.

If the DTC does not return:

Generate readiness code. Refer to READINESS CODE .

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 .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .