Power Distribution Module: Description and Operation

IPDM E/R (INTELLIGENT POWER DISTRIBUTION MODULE ENGINE ROOM)

System Description
- IPDM E/R (Intelligent Power Distribution Module Engine Room) integrates the relay box and fuse block which were originally placed in engine compartment. It controls integrated relay via IPDM E/R control circuit.
- IPDM E/R-integrated control circuit performs ON-OFF operation of relay, CAN communication control, oil pressure switch signal, and hood switch signal reception, etc.
- It controls operation of each electrical part via ECM, BCM and CAN communication lines.

CAUTION: None of the IPDM E/R-integrated relays can be removed.




SYSTEMS CONTROLLED BY IPDM E/R

CAN COMMUNICATION LINE CONTROL
With CAN communication, by connecting each control unit using two communication lines (CAN L line, CAN H line), it is possible to transmit maximum amount of information with minimum wiring. Each control unit can transmit and receive data, and reads necessary information only.

Fail- Safe Control
- When CAN communication with other control units is impossible, IPDM E/R performs fail-safe control. After CAN communication recovers normally, it also returns to normal control.
- Operation of control parts by IPDM E/R during fail-safe mode is as follows:

IPDM E/R STATUS CONTROL
In order to save power, IPDM E/R switches status by itself based on each operating condition.
1. CAN communication status
- CAN communication is normally performed with other control units.
- Individual unit control by IPDM E/R is normally performed.
- When sleep request signal is received from BCM, mode is switched to sleep waiting status.
2. Sleep waiting status
- Process to stop CAN communication is activated.
- All systems controlled by IPDM E/R are stopped. When 3 seconds have elapsed after CAN communication with other control units is stopped, mode switches to sleep status.
3. Sleep status
- IPDM E/R operates in low power mode.
- CAN communication is stopped.
- When a change in CAN communication line is detected, mode switches to CAN communication status.
- When a change hood switch or ignition switch signal is detected, mode switches to CAN communication status.

CAN Communication System Description
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. Modern vehicles are equipped with many electronic control units and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected with 2 communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring. Each control unit transmits/receives data but selectively reads required data only.

CAN Communication Unit
Refer to Information Bus / Description and Operation / "CAN Communication Unit".




Function of Detecting Ignition Relay Malfunction
- When contact point of integrated ignition relay is stuck and cannot be turned OFF, IPDM E/R turns ON parking, license plate, side marker and tail lamps for 10 minutes to indicate ignition relay malfunction.
- When a state of ignition relay having built-in does not agree with a state of ignition switch signal input by a CAN communication from BCM, IPDM E/R lets tail lamp relay operate.