Testing if display is approx. - 40.0° C
-- Disconnect the Engine Coolant Temperature (ECT) Sensor -G62- electrical harness connector.
-- Using a jumper wire, connect the Engine Coolant Temperature (ECT) Sensor -G62- electrical harness connector terminals 1 to 2.
-- Check the value indicated on the scan tool display.
If the value jumps to approx. 140.0° C
-- Switch the ignition off.
-- Replace the Engine Coolant Temperature (ECT) Sensor - G62- Refer to the Repair information.
If indication remains at approx. -40.0° C:
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 Motronic Engine Control Module (ECM) -J623-. Refer to the Repair information.
-- Using a multimeter, check the Engine Coolant Temperature (ECT) Sensor - G62- electrical harness connector terminals to the Motronic Engine Control Module (ECM) -J623- electrical harness connector T60 terminals for an open circuit or a short to voltage, refer to the chart below.
| Engine Coolant Temperature (ECT) Sensor - G62- electrical harness connector terminals | Motronic Engine Control Module (ECM) -J623- electrical connector T60 terminals or test box socket |
|---|---|
| 1 | 42 |
| 2 | 14 |
Specified values: 1.5 Ω Max. and 0 volts with key on and ECM disconnected.
If the specified value was Not obtained:
-- Check the wiring for an open or short circuit to Battery (+).
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If the specified value was obtained:
-- Using a multimeter, check terminal 2 of the ECT sensor to engine ground.
Specified value: 1.5 Ω Max
If the specified value was Not obtained:
-- Check the wiring for an open circuit or high resistance.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If the specified value was obtained:
-- Replace the Motronic Engine Control Module (ECM) -J623-. Refer to the Repair information.