X44 - Check ECT Sensor

- Key "OFF".

- Breakout box installed.

- Connect Powertrain Control Module (PCM) to breakout box.

- Check engine coolant level.

- While measuring the voltage between test pin 7 and test pin 46, start engine and warm engine to operating temperature. Continue to let engine idle.

- Will the voltage drop below 0.45 volt? (Allow sufficient time for voltage to drop, being careful not to overheat engine. If cooling fan turns on, return to Diagnostic Routines for other possible causes of symptom.)

Yes -- Replace PCM. Remove breakout box. Reconnect all components. Re-evaluate symptom.

No -- Check Engine Coolant Temperature (ECT) sensor wires and connector for high resistance. Verify cooling system is operating properly. If OK, replace ECT sensor. Remove breakout box. Reconnect all components. Re-evaluate symptom.