Testing If Display Is Approx. - 40.0°C
-- Disconnect the Engine Coolant Temperature (ECT) Sensor -G62 or G83- electrical harness connector.
-- Using a jumper wire, connect the Engine Coolant Temperature (ECT) Sensor -G62 or G83- 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 or G83-.
If indication remains at approx. -40.0 °C:
Checking wiring
-- Remove the Motronic Engine Control Module (ECM) -J623-. Refer to the Repair Information.
-- Using a multimeter, check the Engine Coolant Temperature (ECT) Sensor -G62 or G83- electrical harness connector terminal 1 to the Motronic Engine Control Module (ECM) -J623- electrical harness connector for an open circuit or a short to voltage, refer to the chart below for the appropriate sensor. Refer to Wiring Diagrams for pin locations.
ECT 1
| Engine Coolant Temperature (ECT) Sensor 1 -G62 - electrical harness connector terminals: | Motronic Engine Control Module (ECM) -J623- electrical connector T60 terminals: |
|---|---|
| 1 | 57 |
| 2 | 14 |
ECT 2
| Engine Coolant Temperature (ECT) Sensor -2 G83- electrical harness connector terminals: | Motronic Engine Control Module (ECM) -J623- electrical connector T94 terminals: |
|---|---|
| 1 | 18 |
| 2 | 12 |
Specified values: 1.5 Ω Max. and 0 volts with ECM disconnected.
If the specified value was Not obtained:
-- Check the wiring for an open or short circuit to voltage.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If no malfunction is detected in the signal circuit:
-- 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 no malfunction is detected in the ground circuit:
-- Replace the Motronic Engine Control Module (ECM) -J623-. Refer to the Repair Information.