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 display approx. 140°C
-- Disconnect the Intake Air Temperature (IAT) Sensor -G42- electrical harness connector -1-.
If indication jumps to approx. -40 °C or -46 °C:
-- End diagnosis and switch ignition off.
-- Replace the Intake Air Temperature (IAT) Sensor -G42 -. Refer to appropriate service information.
If the indication remains at approx. 140 °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 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 Engine Control Module (ECM) -J623- electrical harness connector T60 terminals for resistance.
| Intake Air Temperature (IAT) Sensor -G42 - electrical harness connector terminals | Engine Control Module (ECM) -J623- electrical harness connector T60 terminals or test box socket |
|---|---|
| 1 | 42 |
| 2 | 13 |
Specified value: 1.5 Ω Max.
If the specification was not obtained:
-- Check the wiring for an open circuit, a short circuit to Battery (+), or an open circuit.
-- 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 wiring:
-- Erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
-- Perform a road test to verify repair.
If the DTC does not return:
Generate readiness code. Refer to READINESS CODE .
If the DTC does return and no malfunction is detected in the wiring and the voltage supply was not OK:
-- Replace the Engine Control Module (ECM) -J623-. Refer to appropriate service information.
Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
- Check the DTC memory. DIAGNOSTIC MODE 03 - READ DTC MEMORY .
- If necessary, erase the DTC memory. DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
- If the DTC memory was erased, generate readiness code. READINESS CODE .
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.