Testing If Display Is - 40 °C
-- Disconnect the MAP / IAT sensor -G71 / G42- electrical harness connector.
-- Using a jumper wire, connect the MAP / IAT sensor -G71 / G42- electrical harness connector terminals 1 to 2.
-- Turn the ignition switch ON
-- Check the value indicated on the scan tool display.
-- Switch ignition OFF.
If Indication Jumps To Approx. 140 °C:
-- Replace the MAP / IAT sensor -G71 / G42-.
If indication remains at approx. -40 °C or -46 °C:
Checking Wiring
-- Remove the Engine Control Module (ECM) -J623-.
-- Using a multimeter, check the MAP / IAT sensor -G71 / G42- electrical harness connector terminal 2 to the Engine Control Module (ECM) -J623- electrical harness connector T60 terminal 42 for an open circuit or a short to voltage. Refer to Appropriate System Diagrams for pin locations.
-- Using a multimeter, check the MAP / IAT sensor -G71 / G42- electrical harness connector terminal 1 to the Engine Control Module (ECM) -J623- electrical harness connector T60 terminal 13 for an open, high resistance or a short to voltage. Refer to Appropriate System Diagrams for pin locations.
Specified Resistance: 1.5 Ω Max.
If The Specified Value Was Not Obtained:
-- Check the wiring for an open, high resistance or short circuit to Battery (+).
-- 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:
-- Replace the Engine Control Module (ECM) -J623-.