Starting & Charging System: Overview Nissan Pathfinder III

System Description

Power is supplied at all times

1. to starter motor terminal 2 and
2. through 40A fusible link (letter j, located in the fuse and fusible link box)
3. to ignition switch terminal B.

With the ignition switch in the START position, power is supplied

1. from ignition switch terminal ST
2. to IPDM E/R terminal 21.

With the ignition switch in the ON or START position, power is supplied to IPDM E/R (intelligent power distribution module engine room) CPU.

With the selector lever in the P or N position, power is supplied

1. through A/T assembly terminal 9
2. to IPDM E/R terminal 48.

Ground is supplied at all times

1. to IPDM E/R terminals 38 and 59
2. from body grounds E9, E15 and E24.

Provided that the IPDM E/R receives a starter relay request ON signal from the BCM over the CAN communication lines, the IPDM E/R grounds the starter relay and power is supplied

1. from terminal 19 of the IPDM E/R
2. to terminal 1 of the starter motor.

The starter motor plunger closes and provides a closed circuit between the battery and the starter motor. The starter motor is grounded to the cylinder block. With power and ground supplied, the starter motor operates.

The generator provides DC voltage to operate the vehicle's electrical system and to keep the battery charged.

The voltage output is controlled by the IC regulator.

Power is supplied at all times to generator terminal 3 through

1. 15A fuse (No. 30, located in the fuse and fusible link box).

Terminal 1 supplies power to charge the battery and operate the vehicle's electrical system. Output voltage is controlled by the IC regulator at terminal 3 detecting the input voltage. A pulse width modulated (PWM) signal is sent from terminal 37 of the IPDM E/R to terminal 4 of the generator. The ECM determines the duty cycle of the power generation variable voltage control system. The charging circuit is protected by the 140A fusible link [letter a , located in the fusible link box (battery)].

The generator is grounded through the engine.

With the ignition switch in the ON or START position, power is supplied

1. through 10A fuse [No. 14, located in the fuse block (J/B)]
2. to combination meter terminal 16 for the charge warning lamp.

Ground is supplied to terminal 2 of the combination meter through terminal 2 of the generator. With power and ground supplied, the charge warning lamp will illuminate. When the generator is providing sufficient voltage with the engine running, the ground is opened and the charge warning lamp will go off. If the charge warning lamp illuminates with the engine running, a fault is indicated. The IC regulator warning function activates to illuminate "CHARGE" warning lamp, if any of the following symptoms occur while generator is operating

1. Excessive voltage is produced.
2. No voltage is produced.

Power Generation Variable Voltage Control System Diagram. Scheme 3

Power generation variable voltage control system has been adopted. By varying the voltage to the generator, engine load due to power generation of the generator is reduced and fuel consumption is decreased.

Operation

1. The battery current sensor detects the charging/discharging current of the battery. ECM judges the battery condition based on this signal.
2. ECM judges whether to control voltage according to the battery condition.
3. ECM calculates the target power generation voltage according to the battery condition and sends the calculated value, through CAN lines, as the power generation command value to IPDM E/R.
4. IPDM E/R converts the received power generation command value into the power generation command signal (PWM signal) and sends it to the IC regulator.
5. The IC regulator performs final control over the power generation voltage.
6. When there is no power generation command signal, the generator performs the normal power generation according to the characteristic of the IC regulator.

Note. When any malfunction is detected in the power generation variable voltage control system, power generation is performed according to the characteristic of the IC regulator in the generator.

Scheme 4

1. Battery current sensor is installed to the negative battery cable and it detects the charging/discharging current of the battery and sends the voltage signal to ECM according to the current value. see scheme 27: Identifying Battery Current Sensor