Charging - Service Information: Overview RAM Pickup 2500

DESCRIPTION

The charging system consists of

1. Generator
2. Electronic Voltage Regulator (EVR) circuitry within the Powertrain Control Module (PCM).
3. Ignition switch
4. Battery (refer to «BATTERY SYSTEM - SERVICE INFORMATION»(ref-457788) for information)
5. Battery temperature sensor
6. Check Gauges Lamp (if equipped)
7. Voltmeter (refer to «INSTRUMENT CLUSTER - SERVICE INFORMATION»(ref-457793) for information).
8. Wiring harness and connections (refer to appropriate Wiring Diagrams for information).

Scheme 30

The charging system is turned on and off with the Powertrain Control Module (PCM) 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 receives a voltage input from the generator (5) and also a battery voltage input (7) from the Totally Integrated Power Module (TIPM), it then compares the voltages to the desired voltage programed in the Electronic Voltage Regulator (EVR) 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.

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 charging system is a integral part of the Plug-in Hybrid Electrical Vehicle (PHEV) system. The Electrically Variable (EV) transmissions e-motor A, is responsible for the charging for the 12V and 400V system through regenerative braking when the vehicle is in operation.

OPERATION

The regenerative braking system is used in place of the alternator to charge the 400V system. The regenerative braking system is used to recover kinetic energy into the High Voltage (HV) battery when the vehicle slows or brakes. The regenerative braking occurs almost anytime the driver uses the brakes or coasts at speeds above 6 MPH.

Scheme 31

Scheme 32

1. Disconnect the negative battery cable.
2. Remove the generator drive belt. Refer to «BELT, Serpentine, Removal»(ref-457792-S18686393612012030200000).
3. Unsnap the plastic insulator cap from the B+ output terminal (3). (Scheme 31)
4. Remove the B+ terminal mounting nut at the rear of generator (2). (Scheme 31) Disconnect the terminal from the generator.
5. Disconnect the field wire connector at the rear of the generator (4) by pushing on the connector tab. (Scheme 31) 1 - LOWER BOLTS 2 - REAR BOLT 3 - GENERATOR
6. Remove the one rear vertical generator mounting bolt (2). (Scheme 32)
7. Remove the two front horizontal generator mounting bolts (1). (Scheme 32)
8. Remove the generator from vehicle.

Scheme 33

Scheme 34

Scheme 35

Scheme 36

Scheme 37

1. Disconnect the negative battery cable (1). CAUTION: Do not let the tensioner arm snap back to the freearm position, severe damage may occur to the tensioner.
2. Insert a suitable square drive ratchet into the square hole on the belt tensioner arm (7).
3. Release the belt tension by rotating the tensioner (7) clockwise until the accessory drive belt (4) can be removed from the generator pulley only. Refer to «BELT, Serpentine , Removal»(ref-457792-S18686393612012030200000) .
4. Unsnap the plastic insulator cap from the B+ output terminal (1).
5. Remove the B+ terminal retaining nut (2) and disconnect the B+ terminal eyelet from the generator output stud.
6. Disconnect the field wire electrical connector (3) by pushing on the connector tab.
7. Remove the generator support bracket nuts and bolt (3,4) and remove the support bracket (2).
8. Remove the two generator mounting bolts (1,3) and the generator (2).

Scheme 38

Scheme 39

1. Disconnect both negative battery cables at both batteries.
2. Remove generator drive belt. Refer to «REMOVAL»(ref-457792-S18686393612012030200000) for procedure.
3. Remove upper mounting bracket bolt (2). (Scheme 38)
4. Remove lower mounting bracket bolt and nut (2). (Scheme 38)
5. Remove generator from engine. 1 - B+ CONNECTOR 2 - GENERATOR 3 - FIELD WIRE CONNECTOR
6. Unsnap plastic insulator cap (1) from B+ output terminal.
7. Remove B+ terminal mounting nut at rear of generator. Disconnect terminal from generator.
8. Disconnect field wire connector (3) at rear of generator by pushing on connector tab.

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

The amount of direct 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 positive path to control the strength of the rotor magnetic field. The EVR circuitry monitors system line voltage (B+) and battery temperature (refer to BATTERY SYSTEM - SERVICE INFORMATION 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 grounds the field winding until sensed battery voltage is 0.5 volts above target voltage. A circuit in the PCM cycles the battery positive (high side) of the generator field up to 400 times per second (400Hz), but has the capability to ground the field control wire 100% of the time (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 for additional information. Refer to Operation .