Cold Dr3 - Coolant Sensor
- Connect voltmeter to cavity No. 12 of ECU 13-way connector and ground. Turn ignition switch to "RUN" position. On vehicles with ECU No. MD072035, voltmeter should read 3-5.5 volts with engine cold; 1-2 volts at room temperature and 0-1 volt with engine warm. On vehicles with ECU MD080152, MD082058 or MD082059, voltmeter should read 2-3 volts with engine cold; 1-2 volts at room temperature and 0-1 with engine warm.
- If okay, proceed to COLD DR4. If voltage was incorrect in step 1), turn ignition off. Unplug connector from coolant sensor. Connect ohmmeter leads to sensor terminals. Resistance should be 3,000-17,000 ohms with engine cold; 1000-3000 ohms at room temperature; and 100-1000 ohms with engine warm. If not, replace sensor.
- If resistance is okay, Unplug 13-wire connector from ECU. Connect ohmmeter leads to cavity Nos. 2 and 12. Resistance should be as indicated in step 2). If resistance is okay, replace ECU. If resistance is not okay, repair open wires from coolant sensor to ECU.
Courtesy of CHRYSLER MOTORS.