Diagnosis & Repair
- Connect scan tool to DLC No. 3 connector. See Figure. Turn ignition on. Using scan tool, monitor IAT sensor temperature. If temperature displayed is same as outside temperature, check sensor and ECM connections. Problem is intermittent.
- If temperature displayed is 284°F (140°C) or more, go to step 5). If temperature displayed is -40°F (-40°C), turn ignition off. Disconnect MAF sensor connector. Connect a jumper wire between terminals No. 1 and 2 at MAF sensor wiring harness connector. See Figure. Turn ignition on. Using scan tool, monitor IAT sensor.
- If temperature displayed is 284°F (140°C) or more, replace MAF sensor and retest. If temperature displayed is less than 284°F (140°C), turn ignition off. Remove jumper wire. Access ECM behind glove box. Connect jumper wire between terminals No. 22 (Brown wire) and No. 21 (Blue/Black wire) at ECM E7 connector. See Figure.
- If temperature displayed on scan tool is 284°F (140°C) or more, check and repair wiring harness between MAF sensor connector and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed on scan tool is less than 284°F (140°C), replace ECM and retest.
- Turn ignition off. Disconnect MAF sensor connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace MAF sensor and retest. If temperature displayed is not -40°F (-40°C), turn ignition off.
- Access ECM behind glove box. Disconnect ECM E7 connector. See Figure. Turn ignition on. If temperature displayed is -40°F (-40°C), locate and repair short circuit in wiring harness between MAF sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed by scan tool is not -40°F (-40°C), replace ECM and retest.