Testing if display approx. 140°C:

-- Disconnect the MAF/IAT sensor -G70/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 MAF/IAT sensor -G70/G42-.

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-.

-- Disconnect the ECM harness.

-- Using a multimeter, check the MAF/IAT sensor -G70/G42- electrical harness connector terminal 5 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-.

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 .