you will need to know the different Trouble Codes & testing points of the Charging System & the ECM
Voltage is regulated by cycling the battery voltage to control the strength of the rotor magnetic field.
The EVR circuitry monitors system line voltage (B+) and battery temperature.
It then determines a target charging voltage.
If sensed battery voltage is 0.5 volts or lower than the target voltage, the PCM energizes the field winding until sensed battery voltage is 0.5 volts above target voltage.
A circuit in the PCM cycles the battery side of the generator field up to 100 times per second (100Hz), but has the capability to full field to achieve the target voltage.
If the charging rate cannot be monitored (limp-in), a duty cycle of 25% is used by the PCM in order to have some generator output.
The amount of DC current produced by the generator is controlled by EVR circuitry contained within the PCM. This circuitry is connected in series with the generators second rotor field terminal and its ground
To perform a complete test of the charging system, refer to the appropriate Diagnostic Test Procedures and use of a diagnostic scan tool that is included in instructions of the Scan Tool.
Perform the following inspections before attaching the scan tool.
1.Inspect the battery condition.
2.Inspect condition of battery cable terminals, battery posts, connections at engine block, starter solenoid and relay. They should be clean and tight. Repair as required.
3.Inspect all fuses in both the fuseblock and Power Distribution Center (PDC) for tightness in receptacles. They should be properly installed and tight. Repair or replace as required.
4.Inspect generator mounting bolts for tightness. Replace or tighten bolts if required.
5.Inspect generator drive belt condition and tension. Tighten or replace belt as required.
6.Inspect automatic belt tensioner (if equipped).
7.Inspect generator electrical connections at generator field, battery output, and ground terminal (if equipped). Also check generator ground wire connection at engine (if equipped). They should all be clean and tight. Repair as required.