Grand Cherokee
NOTE:
For circuit identification and wiring diagram, see WIRING DIAGRAMS article. After each repair procedure has been completed, reconnect all components. Perform TEST VER-5
under VERIFICATION TESTS to ensure system is functioning properly.
- Turn ignition on, with engine off. Using scan tool, read EGN COOLANT TMP DEG value. If engine coolant temperature is more than 180°F (82.2°C), allow engine coolant temperature to cool down to 150°F (65.6°C) before proceeding. If engine coolant temperature is 150°F (65.6°C) or less, start engine and monitor scan tool until engine coolant temperature reaches 180°F (82.2°C). If ECT sensor value increases smoothly and reached 180°F (82.2°C), reconnect ECT sensor connector and go to next step. If ECT sensor value increase is erratic or did not reach 180°F (82.2°C), check for cooling system problems and repair as necessary. If cooling system is okay, replace ECT sensor.
- Turn ignition off. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, reconnect all connectors. Start engine. Wiggle ECT sensor connector and wiring harness while monitoring scan tool display. On 4.0L, ECT sensor is mounted in thermostat housing. On 4.7L, ECT is located near front of intake manifold. See Fig 1 . On all models, if GOOD TRIP counter display count changes to "0", repair connector or wiring harness where wiggling caused display to change. If GOOD TRIP counter display count does not change to "0", no problem is indicated at this time. Test is complete. Check for any related technical service bulletins that may apply.