Mazda 2009 RX-8, Service Highlights, Page: 299 / 299

CONTROL SYSTEM
09-40–14
2009 Mazda RX-8 Service Highlights (3452–1U–08C)
Example: ABS HU/CM-related wiring harness open circuit (if DTC is output)
1. Verify the CAN system-related module DTCs and the failed module using the Mazda Modular Diagnostic
System (M-MDS).
2. The wiring harness between the ABS HU/CM and branch B, or the ABS HU/CM itself could have a malfunction
because the DTCs indicating a communication error between the ABS HU/CM and PCM/TCM, in addition to
“Fail” on the ABS HU/CM, are displayed even though communication between the PCM and TCM is normal.
End Of Sie
Module Displayed DTC Probable malfunction location
PCM U0121 ABS HU/CM communication error
TCM U0121 ABS HU/CM communication error
Instrument cluster U1900 CAN system communication error
Module Fail
ABS HU/CM
#
CAN_H
CAN_L
1J
1L
1AI
1AM
PCM
TCM
3X 3W
1C 1G
M
K
: FRONT HARNESS
: DASHBOARD HARNESS
: REAR HARNESS
EPS
CONTROL
MODULE
R O
ABS HU/CU
L K
DLC-2
CONNECTOR
C-07
CONNECTOR
C-0 9
KEYLESS
CONTROL
MODULE
INSTRUMENT
CLUSTER
BRANCH
A
BRANCH
B
BRANCH
C
BRANCH
D
FAIL
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