Testing If Display Approx. -40° C Or Approx. -46° C

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

-- Using a jumper wire, connect the IAT sensor -G42- electrical harness connector terminals 1 to 2.

-- Turn the ignition switch ON.

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

-- Switch the ignition OFF.

If indication jumps to approx. 140 °C:

-- Replace the IAT sensor -G42-. Refer to the Repair Information.

If indication remains at approx. -40 °C or -46 °C:

Checking wiring 

-- Remove the Engine Control Module (ECM) -J623-. Refer to the Repair Information.

-- Disconnect the ECM harness.

-- Using a multimeter, check the IAT sensor -G42- electrical harness connector terminal 1 to the Engine Control Module (ECM) -J623- electrical harness connector T60 terminal 42 for an open circuit or a short to voltage, refer to the wiring diagram.

Specified values: Circuit continuity; 1.5 Ω max; Circuit voltage = 0 volts when disconnected from ECM (with ignition turned on).

If the specified value was Not obtained:

-- Check the wiring for an open, high resistance or short circuit to Battery positive.

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

-- If necessary, repair the faulty wiring connection.

If the specified value was obtained:

-- Using a multimeter, check terminal 2 of the IAT 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 Engine Control Module (ECM) -J623-. Refer to the Repair Information.