Grand Cherokee 2WD L6-4.0L VIN S (1997)
SPEED CONTROL SWITCHES-PCM INPUT
Two separate speed control switch modules are mounted on the steering wheel to the left and right side of the driver's airbag module. Within the
two switch modules, five momentary contact switches, supporting seven different speed control functions are used. The outputs from these
switches are filtered into one input. The Powertrain Control Module (PCM) determines which output has been applied through resistive
multiplexing. The input circuit voltage is measured by the PCM to determine which switch function has been selected.
A speed control indicator lamp, located on the instrument panel cluster is energized by the PCM via the CCD Bus. This occurs when speed control
system power has been turned ON, and the engine is running.
The two switch modules are labeled: ON/OFF SET, RESUME/ACCEL, CANCEL and COAST.
Throttle Position Sensor (TPS)
THROTTLE POSITION SENSOR (TPS)-PCM INPUT
Fig. 9 Throttle Body & Sensors
The Throttle Position Sensor (TPS) is mounted on the throttle body. The TPS is a variable resistor that provides the Powertrain Control Module
(PCM) with an input signal (voltage) that represents throttle blade position. The sensor is connected to the throttle blade shaft. As the position of
the throttle blade changes, the resistance of the TPS changes.
The PCM supplies approximately 5 volts to the TPS. The TPS output voltage (input signal to the PCM) represents the throttle blade position. The
PCM receives an input signal voltage from the TPS. This will vary in an approximate range of from 0.25 volts at minimum throttle opening (idle),
to 4.8 volts at wide open throttle. Along with inputs from other sensors, the PCM uses the TPS input to determine current engine operating
conditions. In response to engine operating conditions, the PCM will adjust fuel injector pulse width and ignition timing.
Transmission Governor Pressure Sensor
TRANSMISSION GOVERNOR PRESSURE SENSOR-PCM INPUT
Provides a signal proportional to the transmission governor pressure. It provides feedback for control of the governor pressure solenoid, which
regulates transmission governor pressure. This input is used with 4-speed electronic transmissions only.
Transmission Park/Neutral Switch
TRANSMISSION PARK/NEUTRAL SWITCH-PCM INPUT
The park/neutral switch is located on the transmission housing and provides an input to the Powertrain Control Module (PCM). This will indicate
that the automatic transmission is in Park, Neutral or a drive gear selection. This input is used to determine idle speed (varying with gear
selection), fuel injector pulse width, ignition timing advance and vehicle speed control operation.
Transmission Temperature Sensor
TRANSMISSION TEMPERATURE SENSOR-PCM INPUT
This input is used in the shift operation for 4-speed electronic transmissions only. The temperature data is used for: torque converter clutch
operation, overdrive shift, low temperature shift compensation, wide open throttle shift strategy and governor pressure transducer calibration.
Transmission fluid temperature readings are supplied to the transmission control module by the thermistor. The temperature readings are used to
