Diagnosis & Repair Procedure
- Perform DTC CONFIRMATION TEST . If DTC P0117 is set, go to next step. If DTC P0117 is not set, problem is intermittent. System is okay at this time. See TROUBLE SHOOTING - NO CODES article.
- Connect scan tool. Turn ignition on. Using scan tool, select ECT parameter. If display reads 401°F (205°C), turn ignition off and go to next step. If display does not read 401°F (205°C), problem is intermittent. System is okay at this time. See TROUBLE SHOOTING - NO CODES article.
- Turn ignition off. Disconnect ECT sensor connector. Turn ignition on. If display reads -40°F (-40°C), replace ECT sensor and go to DTC CONFIRMATION TEST . If display does not read -40°F (-40°C), check for short to ground in Light Green/Red wire between ECT and ECM 28-pin connector C20 terminal No. 12. See Figure . Repair as necessary. If wire is okay, replace ECM and go to DTC CONFIRMATION TEST .