Cherokee 4WD L6-4.0L VIN S (1998)
Oil Pressure Gauge: Description and Operation
SYSTEM OPERATION
The oil pressure gauge gives an indication of the engine oil pressure. The instrument cluster circuitry controls the gauge pointer position. The
instrument cluster circuitry calculates the proper gauge pointer position based upon an engine oil pressure message received from the Powertrain
Control Module (PCM) on the Chrysler Collision Detection (CCD) data bus.
The PCM uses an input from the engine oil pressure sensor and internal programming to decide what engine oil pressure message is required. The
PCM then sends the proper message to the instrument cluster on the CCD data bus. If the PCM message indicates that oil pressure is low, the
instrument cluster circuitry moves the gauge needle to below the zero graduation on the gauge face, and turns on the Check Gauges lamp.
The engine oil pressure sensor is installed in a threaded hole that penetrates an oil passage of the engine. The engine oil pressure sensor contains a
flexible diaphragm and a variable resistor coil. The diaphragm moves in response to changes in the engine oil pressure, which changes the internal
electrical resistance of the sensor.
