Jeep Cherokee
 Service Manual
Charging system » Description and operation
Charging system


The charging system consists of:

  •  Generator
  •  Electronic Voltage Regulator (EVR) circuitry within the Powertrain Control Module (PCM)
  •  Ignition switch (refer to Group 8D, Ignition System for information)
  •  Battery (refer to Group 8A, Battery for information)
  •  Battery temperature sensor
  •  Generator Lamp (if equipped)
  •  Check Gauges Lamp (if equipped)
  •  Voltmeter (refer to Group 8E, Instrument Panel and Gauges for information)
  •  Wiring harness and connections (refer to Group 8W, Wiring for information)


The charging system is turned on and off with the ignition switch. The system is on when the engine is running and the ASD relay is energized. When the ASD relay is on, voltage is supplied to the ASD relay sense circuit at the PCM. This voltage is connected through the PCM and supplied to one of the generator field terminals (Gen. Source +) at the back of the generator.

The amount of DC current produced by the generator is controlled by the EVR (field control) circuitry contained within the PCM. This circuitry is connected in series with the second rotor field terminal and ground.

A battery temperature sensor, located in the battery tray housing, is used to sense battery temperature.

This temperature data, along with data from monitored line voltage, is used by the PCM to vary the battery charging rate. This is done by cycling the ground path to control the strength of the rotor magnetic field. The PCM then compensates and regulates generator current output accordingly.

All vehicles are equipped with On-Board Diagnostics (OBD). All OBD-sensed systems, including EVR (field control) circuitry, are monitored by the PCM.

Each monitored circuit is assigned a Diagnostic Trouble Code (DTC). The PCM will store a DTC in electronic memory for certain failures it detects. Refer to On-Board Diagnostics in Group 25, Emission Control System for more DTC information.

The Check Gauges Lamp (if equipped) monitors: charging system voltage, engine coolant temperature and engine oil pressure. If an extreme condition is indicated, the lamp will be illuminated. This is done as reminder to check the three gauges. The signal to activate the lamp is sent via the CCD bus circuits.

The lamp is located on the instrument panel.

Refer to Group 8E, Instrument Panel and Gauges for additional information.

    More about «Description and operation»:

    Charging system


    Battery temperature sensor

    Electronic voltage regulator

    Jeep Cherokee Service Manual / Charging system / Description and operation / Charging system

    Jeep Cherokee Service Manual


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