Diagnosis & Repair
WARNING: This page is about a different car, the 2000 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.
- Connect scan tool to Data Link Connector (DLC) No. 3. See Figure. Turn ignition on. Using scan tool, monitor IAT sensor temperature. If temperature displayed on scan tool is same as outside temperature, problem is intermittent. Check component and ECM connections. If temperature displayed on scan tool is 284°F (140°C) or more, go to step 4. If temperature displayed on scan tool is -40°F (-40°C), go to next step.
- Turn ignition off. Disconnect MAF meter harness connector. Connect a jumper wire between terminals No. 4 (Yellow/Black wire) and No. 5 (Brown wire) at MAF meter harness connector. See Figure. Turn ignition on. Using scan tool, monitor IAT sensor temperature. If temperature displayed on scan tool is 284°F (140°C) or more, replace MAF meter. If temperature displayed on scan tool is less than 284°F (140°C), go to next step.
- Turn ignition off. Remove jumper wire. Access ECM below stereo, behind instrument panel, just in front of center console. On models with 4A/T transmission, connect a jumper wire by backprobing between terminals No. 22 (Yellow/Black wire) and No. 18 (Brown wire) at ECM harness connector E8. See Figure. On models without 4A/T transmission, connect a jumper wire by backprobing between terminals No. 3 (Yellow/Black wire) and No. 9 (Brown wire) at ECM harness connector E5. See Figure. On all models, temperature displayed on scan tool should be 284°F (140°C) or more. If temperature displayed on scan tool is as specified, repair open in wiring between MAF meter and ECM. See WIRING DIAGRAMS article. If temperature displayed on scan tool is not as specified, replace ECM.
- Turn ignition off. Disconnect MAF meter harness connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace MAF meter. If temperature displayed on scan tool is not -40°F (-40°C), go to next step.
- Turn ignition off. Access ECM below stereo, behind instrument panel, just in front of center console. On models with 4A/T transmission, disconnect ECM harness connector E8. See Figure. On models without 4A/T transmission, disconnect ECM harness connector E5. See Figure. On all models, turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), repair short in wiring between MAF meter and ECM. See WIRING DIAGRAMS article. If temperature displayed on scan tool is not -40°F (-40°C), replace ECM.