Charging - Service Information: Overview Dodge Durango III

DESCRIPTION

The charging system consists of

1. Generator
2. Generator decoupler pulley (if equipped)
3. Electronic Voltage Regulator (EVR) circuitry within the Powertrain Control Module (PCM)
4. Ignition switch
5. Battery (refer to «BATTERY SYSTEM - SERVICE INFORMATION»(ref-465932) for information)
6. Generator lamp (if equipped)
7. Check gauges lamp (if equipped)
8. Voltmeter (refer to «INSTRUMENT CLUSTER - SERVICE INFORMATION»(ref-465951) for information)
9. Wiring harness and connections (refer to appropriate Wiring for information)

Scheme 36

On gasoline powered engines, the charging system is turned on and off with the PCM (Powertrain Control Module) and ignition switch with engine running. On diesel powered engines, the charging system is turned on and off with the ECM (Engine Control Module) and ignition switch with engine running. The field circuit will not be energized until engine is running and ignition switch on. This voltage is connected through the PCM and supplied to one of the generator field terminals (Gen. Source B+) at the back of the generator. The generator is internally grounded. The generator regulates the field using pin-1 of the field connector (high side driver).

The generator is driven by the engine through a serpentine belt and pulley, or a decoupler pulley arrangement.

The PCM, or ECM receives a voltage input from the generator (5) and also a battery voltage input (7) from the TIPM (Totally Integrated Power Module), it then compares the voltages to the desired voltage programed in the EVR (Electronic Voltage Regulator) software, and, if there is a difference it sends a signal to the generator EVR circuit to increase or decrease output. It uses a Pulse Width Modulation (PWM) to send signals to the generator circuitry to control the amount of output from the generator. The amount of DC current produced by the generator is controlled by the EVR circuitry contained within the generator.

All vehicles are equipped with On-Board Diagnostics (OBD). All OBD-sensed systems, including EVR 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.

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 lamp is located on the instrument panel. for additional information. Refer to INDICATORS, INSTRUMENT CLUSTER , DESCRIPTION .

Voltage is monitored at the B+ terminal stud to insure it is connected. If the B+ cable is loose, the PCM will shut down generator field. Because of this new feature, pin-2 of the field connector is internally connected to the B+ terminal.

The generator used with diesel engines is internally regulated. The generator and ECM communicate for diagnostics, etc. If the generator regulator becomes disconnected from the ECM, it will still operate, but in a default mode.

The generator is belt-driven by the engine using a serpentine type drive belt. It is serviced only as a complete assembly. If the generator fails for any reason, the entire assembly must be replaced.

OPERATION

As the energized rotor begins to rotate within the generator, the spinning magnetic field induces a current into the windings of the stator coil. Once the generator begins producing sufficient current, it also provides the current needed to energize the rotor.

The stator winding connections deliver the induced alternating current to 6 positive and 6 negative diodes for rectification. From the diodes, rectified direct current is delivered to the vehicle electrical system through the generator battery terminal.

Noise emitting from the generator may be caused by: worn, loose or defective bearings; a loose or defective drive pulley; incorrect, worn, damaged or misadjusted fan drive belt; loose mounting bolts; a misaligned drive pulley or a defective stator or diode.

Scheme 37

Scheme 38

1. Disconnect and isolate the negative battery cable
2. Unplug the field circuit (3) from generator.
3. Remove the B+ terminal nut (1) and wire (2).
4. Remove the serpentine belt. Refer to «BELT, SERPENTINE , REMOVAL»(ref-465940-S20367993122012042300000) .
5. Remove the lower front generator mounting retainer (5).
6. Remove the three mounting retainers.
7. Remove the generator from the vehicle.

Scheme 39

Scheme 40

1. Disconnect and isolate the negative battery cable.
2. Remove the air cleaner body. Refer to «BODY, AIR CLEANER , REMOVAL»(ref-465933-S00984640022012042300000) or «BODY, AIR CLEANER , REMOVAL , 5.7L»(ref-465934-S30952154692012042300000) .
3. Remove the serpentine belt. Refer to «BELT, SERPENTINE , REMOVAL»(ref-465940-S20367993122012042300000) .
4. Unsnap the plastic insulator cap from the B+ output terminal.
5. Remove the B+ terminal mounting nut at the rear of the generator. Disconnect the terminal from the generator.
6. Disconnect the field wire connector (3) at the rear of the generator by pushing on the connector tab.
7. Remove two generator mounting bolts (1).
8. Remove the generator (2) from vehicle.

The Electronic Voltage Regulator (EVR) is not a separate component. It is actually a voltage regulating circuit located within the Powertrain Control Module (PCM). The EVR is not serviced separately. If replacement is necessary, the PCM must be replaced.

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.

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 (refer to Battery Temperature Sensor for more information). 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.