Control; Controller Area Network (Can) Outline; Controller Area Network (Can) System Wiring Diagram; Controller Area Network (Can) Operation - Mazda RX-8 2004 Service Highlights

Control

• In order to maintain the optimum battery positive voltage, the PCM calculates the target generator current
(target output current) and target excitation current according to the generator rotation speed at that time.
• The generator rotation speed is calculated based on the ratio between the generator pulley and eccentric shaft
pulley, and the engine speed.
• The target output current is calculated from the difference obtained by comparison between present battery
positive voltage and target battery positive voltage (regulated voltage), calculated based on the IAT, engine
speed, and vehicle speed.
• When an electrical load is applied, power consumption increases and the battery positive voltage drops,
increasing the target engine speed at idling.
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CONTROLLER AREA NETWORK (CAN) OUTLINE

• Used for communication with the EPS control module, TCM (AT), keyless control module, instrument cluster,
ABS HU/CM or DSC HU/CM and TPMS control module.
• By the adoption of the CAN, wiring between the PCM and other units has been simplified.
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CONTROLLER AREA NETWORK (CAN) SYSTEM WIRING DIAGRAM

• The PCM performs communication of vehicle information with the EPS control module, TCM (AT), keyless
control module, instrument cluster, ABS HU/CM or DSC HU/CM, TPMS control module and DLC-2.
EPS
CONTROL
MODULE
2M
4V
PCM
4S
TWISTED PAIR
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CONTROLLER AREA NETWORK (CAN) OPERATION

• The PCM communicates the following vehicle information with the EPS control module, TCM (AT), keyless
control module, steering angle sensor, instrument cluster, ABS HU/CM or DSC HU/CM, TPMS control module
via CAN line.
CAN Signal-Chart (Between PCM and other units)
Signal
PCM
OUT
Immobilizer-related
information
Engine speed OUT
OUT
Vehicle speed
Throttle valve opening
OUT
angle
01–40–40
CONTROL SYSTEM
AT
TCM
2K 1V 1Y
O R
WITH ABS
ABS HU/CM
I
H
WITH DSC
DSC HU/CM
EPS
control TCM (AT)
module
– –
IN – –
IN IN
IN –
IN – OUT
– IN
KEYLESS
CONTROL
MODULE
3A 3B
E G
TPMS
CONTROL
MODULE
Multiplex module
ABS HU/
Keyless
CM
control
DSC HU/
module
CM
– IN
– OUT
–
IN
IN
– –
– –
–
–
IN
CHU014000140S51
CHU014000140S52
WITH DSC
STEERING
ANGLE
SENSOR
E F
1J
INSTRUMENT
CLUSTER
1L
F E
DLC-2
: CAN_H
: CAN_L
CHU0140S088
CHU014000140S53
OUT: Output (sends signal)
IN: Input (receives signal)
TPMS Steering
Instrument
control angle
cluster
module sensor
– –
– –
–
–
IN
IN –
– –
– –
–
–
IN
IN
–
–