SENSOR, Coolant Temperature
DESCRIPTION
DESCRIPTION
The Engine Coolant Temperature (ECT) sensor is used to sense engine coolant temperature. The sensor protrudes into the thermostat housing.
The ECT sensor is a two-wire Negative Thermal Coefficient (NTC) sensor. Meaning, as engine coolant temperature increases, resistance (voltage) in the sensor decreases. As temperature decreases, resistance (voltage) in the sensor increases.
OPERATION
OPERATION
At key-on, the Powertrain Control Module (PCM) sends out a regulated 5 volt signal to the ECT sensor. The PCM then monitors the signal as it passes through the ECT sensor to the sensor ground (sensor return).
When the engine is cold, the PCM will operate in Open Loop cycle. It will demand slightly richer air-fuel mixtures and higher idle speeds. This is done until normal operating temperatures are reached.
The PCM uses inputs from the ECT sensor for the following calculations:
- For engine coolant temperature gauge operation through CCD or PCI (J1850) communications
- Injector pulse-width
- Spark-advance curves
- ASD relay shut-down times
- Idle Air Control (IAC) motor key-on steps
- Pulse-width prime-shot during cranking
- O2 sensor closed loop times
- Purge solenoid on/off times
- EGR solenoid on/off times (if equipped)
- Leak Detection Pump operation (if equipped)
- Radiator fan relay on/off times (if equipped)
- Target idle speed
3.6L
3.6L
Hot, pressurized coolant can cause injury by scalding. Cooling system must be partially drained before removing the coolant temperature sensor.
WARNING:
 |
- Disconnect the negative battery cable.
- Partially drain the cooling system.
-
Remove the drivers side front inner wheel splash shield (Refer to 23 - Body/Exterior/SHIELD, Splash - Removal)
.
- Disconnect the electrical connector (1) from the engine coolant sensor (2).
-
Remove the sensor from the cylinder head.
2.8L
2.8L
 |
Do not remove or loosen the coolant pressure/vent cap, cylinder block drain plugs, or the draincock when the system is hot and under pressure because serious burns from the coolant can occur.
WARNING:
| NOTE: |
The temperature sensor is located on the thermostat housing (2). In order to gain access to the sensor. You must remove the thermostat housing (2). |
-
Remove the thermostat
housing (2) (Refer to 07 - Cooling/Engine/THERMOSTAT
- Removal)
.
-
Remove the coolant temperature sensor (4) from thermostat housing
(1).
3.6L
3.6L
|
- Apply sealant to ECT sensor threads (new replacement ECT sensors will have sealant already applied).
- Install ECT sensor (2) into intake manifold. Tighten to 11 N·m (8 ft. lbs.) torque.
-
Connect electrical connector (1).
- Install the drivers side front inner wheel splash shield (Refer to 23 - Body/Exterior/SHIELD, Splash - Installation) .
- Lower vehicle.
- Connect the negative battery cable.
-
Fill cooling system. (Refer to 07 - Cooling - Standard Procedure)
.
2.8L
2.8L
|
-
Install coolant temperature
sensor (4) in thermostat housing (1). Tighten sensor (4) to 11 N·m
(97 in. lbs.).
-
Install the thermostat
housing (2) onto engine (Refer
to 07 - Cooling/Engine/THERMOSTAT - Installation)
.