Body Control System: Overview Nissan Murano Z50

System Description

BCM (Body Control Module) controls the operation of various electrical units installed on the vehicle.

Description

1. BCM reads combination switch (lighting switch, wiper switch) status, and controls various electrical component according to the results.
2. BCM reads information of a maximum of 20 switches by combining five output terminals (OUTPUT 1-5) and five input terminals (INPUT 1-5).

Operation Description

1. BCM activates transistors of output terminals (OUTPUT 1-5) periodically, and allows current to flow in turn.
2. If any (1 or more) switches are turned ON, circuit of output terminals (OUTPUT 1-5) and input terminals (INPUT 1-5) becomes active.
3. At this time, transistors of output terminals (OUTPUT 1-5) are activated to allow current to flow. When voltage of input terminals (INPUT 1-5) corresponding to that switch changes, interface in BCM detects voltage change, and BCM determines that switch is ON.

Scheme 136

Scheme 137

1. BCM reads operation status of combination switch using combinations shown in table below.

Note. Headlamp has a dual system switch.

Scheme 138

1. When lighting switch 1ST position is turned ON, contact in combination switch turns ON. At this time if OUTPUT 4 transistor is activated, BCM detects that voltage changes in INPUT 5.
2. When OUTPUT 4 transistor is ON, BCM detects that voltage changes in INPUT 5, and judges that lighting switch 1ST position is ON. Then BCM sends tail lamp ON signal to IPDM E/R using CAN communication.
3. When OUTPUT 4 transistor is activated again, BCM detects that voltage changes in INPUT 5, and recognizes that lighting switch 1ST position is continuously ON.

1: LIGHTING SWITCH 1ST POSITION

Note. Each OUTPUT terminal transistor is activated at 10 ms intervals. Therefore after switch is turned ON, electrical loads are activated with time delay. But this time delay is so short that it cannot be detected by human senses.

Operation Mode

Combination switch reading function has operation modes shown below.

Scheme 139

1. Normal status When BCM is not in sleep status, OUTPUT terminals (1-5) send out ON signal every 10 ms.
2. Sleep status When BCM is in sleep status, transistors of OUTPUT 1 and 5 stop the output, and BCM enters low power mode. Mean while OUTPUT 2, 3, and 4 send out ON signal every 60 ms, and accept input from lighting switch system.

Operation Procedure

1. Touch "BCM" on "SELECT TEST ITEM" screen.
2. Touch "WORK SUPPORT" on "SELECT DIAG MODE" screen.
3. Touch item on "SELECT WORK ITEM" screen.
4. Touch "START".
5. Touch "CHANGE SET".
6. The setting will be changed and "RESETTING COMPLETED" will be displayed.
7. Touch "END".