Testing if display approx. 140° C:

-- Disconnect the IAT sensor - G42- electrical harness connector.

-- Check the value indicated on the scan tool display.

If indication jumps to approx. -40° C or -46° C:

-- Switch ignition off.

-- Replace the IAT sensor - G42- Refer to the appropriate Service Information.

If the indication remains at approx. 140° C

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 appropriate Service Information.

-- Disconnect the ECM harness.

-- Using a multimeter, check the IAT sensor - G42- electrical harness connector terminal 1 to engine ground.

Specified value: OL or no continuity.

If the specified value was Not obtained:

-- Check the wiring for a short circuit to Ground.

-- If necessary, repair the faulty wiring connection.

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

If no malfunction is detected in the wiring and the sensor resistance was OK:

-- Replace the Motronic Engine Control Module (ECM) -J623-. Refer to the appropriate Service Information.

Final Procedures 

After the 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 .