Grand Cherokee 2WD L6-4.0L VIN S (1997)
Fig. 7 ECT Sensor - 4.0
The engine coolant temperature sensor is installed in the thermostat housing and protrudes into the water jacket. The sensor provides an input
voltage to the Powertrain Control Module (PCM) relating coolant temperature. The PCM uses this input along with inputs from other sensors to
determine injector pulse width and ignition timing. As coolant temperature varies, the coolant temperature sensor resistance changes. The change
in resistance results in a different input voltage to the PCM.
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.
Five Volt Sensor Supply-Primary
FIVE VOLT SENSOR SUPPLY-PRIMARY
Supplies the required 5 volt power source to the Crankshaft Position (CKP) sensor, Camshaft Position Sensor (CPS), Manifold Absolute Pressure
(MAP) sensor and Throttle Position Sensor (TPS).
Five Volt Sensor Supply-Secondary
FIVE VOLT SENSOR SUPPLY-SECONDARY
Supplies the required 5 volt power source to the transmission pressure sensor and the vehicle speed sensor.
Fuel Level Sensor
FUEL LEVEL SENSOR-PCM INPUT
The fuel level sensor (fuel gauge sending unit) sends a signal to the Powertrain Control Module (PCM) to indicate fuel level. The purpose of this
feature is to prevent a false setting of misfire and fuel system monitor trouble codes if the fuel level is less than approximately 15 percent, or
more than approximately 85 percent of its rated capacity It is also used to send a signal for fuel gauge operation via the CCD bus circuits.
Generator Output
GENERATOR OUTPUT-PCM INPUT
Provides a charging system voltage input to the Powertrain Control Module (PCM). It is sensed at the battery input to the PCM.
Ignition Circuit Sense
IGNITION CIRCUIT SENSE-PCM IN PUT
The ignition circuit sense input tells the Powertrain Control Module (PCM) the ignition switch has energized the ignition circuit.
Intake Manifold Air Temperature Sensor
INTAKE MANIFOLD AIR TEMPERATURE SENSOR-PCM INPUT
