Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Testing If Scan Tool Display Is Approx. - 40.0° C
-- Disconnect the Intake Air Temperature (IAT) Sensor - G42- electrical harness connector -1-.
-- Using a jumper wire, connect the Intake Air Temperature (IAT) Sensor - G42- electrical harness connector terminals 1 to 2.
-- Switch the ignition on.
-- Check the value indicated on the scan tool display.
Specified value: scan tool display approx. 140.0° C
-- End diagnosis and switch ignition off.
If the specified value was obtained:
-- Replace the Intake Air Temperature (IAT) Sensor - G42 -. Refer to appropriate service information.
-- Go to Final procedures
If the specified value was not obtained:
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 appropriate service information.
-- Using a Multimeter, check the Intake Air Temperature (IAT) Sensor - G42- electrical harness connector terminals to the Motronic Engine Control Module (ECM) - J623- electrical harness connector T60 terminals for an open circuit according to the wiring diagram.
| Intake Air Temperature (IAT) Sensor - G42- electrical harness connector terminals | Motronic Engine Control Module (ECM) - J623- electrical connector T60 terminals or test box socket |
|---|---|
| 1 | 42 |
| 2 | 13 |
Specified value: 1.5 Ω Max.
If the specified value was not obtained:
-- Check the wiring for a short circuit to Battery voltage, or an open circuit.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
-- Go to Final procedures
If the specified value was obtained:
-- Replace the Motronic Engine Control Module (ECM) -J623 -. Refer to appropriate service information.
-- Go to Final procedures
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.