See Figures 1 and 2
The PCM determines engine coolant temperature from the coolant temperature sensor. The combination coolant temperature sensor has two elements. One supplies a coolant temperature signal to the PCM, and the other element provides a coolant temperature signal to the instrument panel gauge cluster. As coolant temperature changes, the coolant temperature sensor's resistance changes, resulting in a different input voltage to the PCM and gauge. When the air is cold, the PCM provides a slightly richer air/fuel ratio and higher idle speed until the proper normal operating temperature is reached.
See Figures 3 and 4
- Visually check the connector, making sure it is attached properly and all of the terminals are straight, tight and free of corrosion.
- With the ignition OFF , detach the electrical connector from the coolant temperature sensor.
- Connect a digital ohmmeter to terminals A and B (shown in the accompanying figure). The ohmmeter should read as follows:
- With the engine and sensor at normal operating temperature, about 200°F, the DVOM should read about 700-1,000 ohms.
- With the engine and sensor at room temperature, about 70°F, the DVOM should read about 7,000-13,000 ohms.
REMOVAL & INSTALLATION
See Figures 3 and 4
New sensors have sealant already applied to the threads.
- Disconnect the negative battery cable.
- Drain the coolant into a suitable container, until it is at a level below the coolant temperature sensor.
- Detach the coolant temperature sensor electrical connector.
- Use a suitable wrench or ratchet, as applicable, to loosen and remove the coolant temperature sensor.
- Install the coolant sensor and tighten to 60 inch lbs. (7 Nm) for 1995 vehicles or to 13.5 ft. lbs. (18 Nm) for 1996-99 vehicles.
- Attach the electrical connector to the coolant temperature sensor.
- Connect the negative battery cable. Fill the cooling system with the proper type and quantity of coolant.