Jeep Cherokee (XJ): Five volt sensor supplies-primary and secondary. Fuel level sensor-pcm input. Engine coolant temperature sensor-pcm input
DESCRIPTION Two different Powertrain Control Module (PCM)
five volt supply circuits are used; primary and secondary. OPERATION These 2 circuits will: DESCRIPTION The fuel level sensor (fuel gauge sending unit) is
located on the fuel pump module. OPERATION Refer to Fuel Gauge Sending Unit in the Fuel
Delivery section for information. DESCRIPTION The Engine Coolant Temperature (ECT) sensor is
used to sense engine coolant temperature. The sensor
protrudes into an engine water jacket.
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 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 airfuel
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:Five volt sensor supplies-primary
and secondary
Fuel level sensor-pcm input
Engine coolant temperature
sensor-pcm input
Automatic shutdown (asd) relay sense-pcm input. Battery voltage-pcm input. Brake switch-pcm input
Extended idle switch-pcm input. Oxygen sensor-pcm input. Ignition circuit sense-pcm input
Other materials:
Heater and air conditioner. Heater and air conditioner control. Heater core
Heater and air conditioner
DESCRIPTION
All vehicles are equipped with a common heater-
A/C housing assembly (Fig. 4). The system combines
air conditioning, heating, and ventilating capabilities
in a single unit housing mounted under the instrument
panel. On heater-only systems, the evaporator
...