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.

Fig 1: 2-Pin Electrical Connector & Terminals

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

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

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 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.

Fig 2: 2-Pin Electrical Connector & Terminals

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

ECT 1

Engine Coolant Temperature (ECT) Sensor 1 -G62 - electrical harness connector terminals	Motronic Engine Control Module (ECM) -J623- electrical connector T60 terminals or test box socket
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 or test box socket
1	18
2	12

Specified Values: 1.5 Ω Max. And 0 Volts Disconnected From Ecm.

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 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.