Page 851 of 909
![MAZDA 6 2002 Workshop Manual Suplement T–40
ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]
Flowchart
•Use the following flowchart to verify the cause of the trouble.
End Of Sie
Repair the malfunctioning part by
following the DT MAZDA 6 2002 Workshop Manual Suplement T–40
ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]
Flowchart
•Use the following flowchart to verify the cause of the trouble.
End Of Sie
Repair the malfunctioning part by
following the DT](/manual-img/28/57057/w960_57057-850.png)
T–40
ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]
Flowchart
•Use the following flowchart to verify the cause of the trouble.
End Of Sie
Repair the malfunctioning part by
following the DTC inspection.A
Inspect the power supply and the ground circuits for any units
that do not respond.
Are they normal?
Repair the malfunctioning part.A
A
B START
Using the SST (WDS or equivalent), verify if DTCs are displayed for PCM, TCM, ABS (ABS/TCS) HU/CM (with ABS (ABS/TCS)),
DSC HU/CM (with DSC), 4WD control module and instrument cluster.
Are any DTCs displayed?
Ye s
Are any DTCs other than the following displayed?
PCM: U0073, U0101, U0121, U0155
TCM: U0073, U0100
ABS (ABS/TCS) HU/CM, DSC HU/CM,
Instrument cluster: U1900, U2516
4WD control module: U0100, U0101, U0121
NoEND No
No Ye s
Are any of the following DTCs displayed?
PCM: U0073, U0101, U0121, U0155
TCM: U0073, U0100
ABS (ABS/TCS) HU/CM, DSC HU/CM,
Instrument cluster: U1900, U2516
4WD control module: U0100, U0101, U0121
Ye s
Ye s Narrow down CAN system malfunction location.
Using the SST (WDS or equivalent), verify if DTCs are displayed
for PCM, TCM, ABS (ABS/TCS) HU/CM, DSC HU/CM, 4WD
control module and instrument cluster.
Are any DTCs displayed?
No
Using the SST (WDS or equivalent), clear DTCs stored in
each module.
END
Ye s
No
Turn the ignition switch to the LOCK position.
Inspect the wiring harness and connector between
any unit that does not respond and the DLC-2.
PCM
—DLC-2 (except MZR-CD (RF Turbo))
2R—CAN_L
2U—CAN_H
PCM—DLC-2 (MZR-CD (RF Turbo))
39—CAN_L
13—CAN_H
TCM—DLC-2
2J—CAN_L
2M—CAN_H
ABS (ABS/TCS) HU/CM—DLC-2
X—KLN
DSC HU/CM—DLC-2
AB—KLN
4WD control module—DLC-2
H—CAN_L
G—CAN_H
Instrument cluster—DLC-2
2W—CAN_L
2X—CAN_H
Are the wiring harnesses and connectors normal? Is there a response from the PCM, TCM, ABS (ABS/TCS) HU/CM,
DSC HU/CM, 4WD control module and/or instrument cluster?
No Ye s
No
Ye s Repair the malfunctioning part by following the DTC inspection.
Repair the malfunctioning part.
A6E8162L101
Page 854 of 909
T–42
ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]
PROCEDURES FOR DETERMINING THE LOCATION OF A MALFUNCTIONA6E816255430204System Wiring Diagram
PCM
1. Check the display of DTC U0101, U0121 and/or U0155, using the SST (WDS or equivalent). (See T–41 DTC
TABLE.)
2. Referring to the following table, determine the malfunctioning part of the CAN system.
2WD
X: Normal
—: Communication error
PCMWIRING
HARNESS A
TWIST PAIRWIRING
HARNESS BWIRING
HARNESS C
INSTRUMENT
CLUSTER ABS (ABS/TCS)
HU/CM
OR
DSC HU/CM
TCM4WD
CONTROL
MODULE
WIRING
HARNESS EWIRING
HARNESS G
WIRING
HARNESS D
WIRING
HARNESS F
PCMWIRING
HARNESS A
INSTRUMENT
CLUSTER ABS (ABS/TCS)
HU/CM
OR
DSC HU/CM
WIRING
HARNESS C
WIRING
HARNESS B
2WD
4WD
A6E81621102
ModuleCommunication status
Malfunction location
ABS (ABS/TCS) HU/CM
DSC HU/CMInstrument cluster
PCM——•Wiring harness A
•PCM
—X•Wiring harness B
•ABS (ABS/TCS) HU/CM
•DSC HU/CM
X—•Wiring harness C
•Instrument cluster
Page 855 of 909
![MAZDA 6 2002 Workshop Manual Suplement ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]
T–43
T
4WD
X: Normal
—: Communication error
TCM
1. Access and monitor the “PCM_MSG”, “ABS_MSG”, “AWD_MSG” and “IC_MSG” of PID MAZDA 6 2002 Workshop Manual Suplement ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]
T–43
T
4WD
X: Normal
—: Communication error
TCM
1. Access and monitor the “PCM_MSG”, “ABS_MSG”, “AWD_MSG” and “IC_MSG” of PID](/manual-img/28/57057/w960_57057-854.png)
ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]
T–43
T
4WD
X: Normal
—: Communication error
TCM
1. Access and monitor the “PCM_MSG”, “ABS_MSG”, “AWD_MSG” and “IC_MSG” of PID using the SST (WDS
or equivalent).
2. Referring to the PID/DATA MONITOR, confirm the display status of the PID. (See T–41 PID/DATA MONITOR
TABLE.)
3. Referring to the following table, determine the malfunctioning part of the CAN system.
X: Normal
—: Communication error
ABS (ABS/TCS) HU/CM or DSC HU/CM
1. Access and monitor the “PCM_MSG”, “TCM_MSG”, “AWD_MSG” and “IC_MSG” of PID using the SST (WDS
or equivalent).
2. Referring to the PID/DATA MONITOR, confirm the display status of the PID. (See T–41 PID/DATA MONITOR
TABLE.)
3. Referring to the following table, determine the malfunctioning part of the CAN system.
2WD
X: Normal
—: Communication error
ModuleCommunication status
Malfunction location
TCMABS (ABS/TCS) HU/CM
DSC HU/CMInstrument cluster
PCM———•Wiring harness A
•PCM
—XX•Wiring harness B
•TCM
X—X•Wiring harness D
•ABS (ABS/TCS) HU/CM
•DSC HU/CM
XX—•Wiring harness E
•Wiring harness G
•Instrument cluster
X——•Wiring harness C
ModuleCommunication status
Malfunction location
PCMABS (ABS/TCS)
HU/CM
DSC HU/CM4WD control
moduleInstrument cluster
TCM————•Wiring harness B
•TCM
—XXX•Wiring harness A
•PCM
X—XX•Wiring harness D
•ABS (ABS/TCS)
HU/CM
•DSC HU/CM
XX—X•Wiring harness F
•4WD control
module
XXX—•Wiring harness G
•Instrument cluster
X———•Wiring harness C
XX——•Wiring harness E
ModuleCommunication status
Malfunction location
PCM Instrument cluster
•ABS (ABS/TCS) HU/CM
•DSC HU/CM——•Wiring harness B
•ABS (ABS/TCS) HU/CM
•DSC HU/CM
—X•Wiring harness A
•PCM
X—•Wiring harness C
•Instrument cluster
Page 856 of 909
![MAZDA 6 2002 Workshop Manual Suplement T–44
ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]
4WD
X: Normal
—: Communication error
4WD control module
1. Check the display of DTC U0100, U0101 and/or U0121, using the SST (WDS or equi MAZDA 6 2002 Workshop Manual Suplement T–44
ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]
4WD
X: Normal
—: Communication error
4WD control module
1. Check the display of DTC U0100, U0101 and/or U0121, using the SST (WDS or equi](/manual-img/28/57057/w960_57057-855.png)
T–44
ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]
4WD
X: Normal
—: Communication error
4WD control module
1. Check the display of DTC U0100, U0101 and/or U0121, using the SST (WDS or equivalent). (See T–41 DTC
TABLE.)
2. Referring to the following table, determine the malfunctioning part of the CAN system.
X: Normal
—: Communication error
Instrument Cluster
1. Access and monitor the “PCM_MSG”, “ABS_MSG”, “AWD_MSG” and “TCM_MSG” of PID using the SST
(WDS or equivalent).
2. Referring to the PID/DATA MONITOR, confirm the display status of the PID. (See T–41 PID/DATA MONITOR
TABLE.)
3. Referring to the following table, determine the malfunctioning part of the CAN system.
ModuleCommunication status
Malfunction location
PCM TCM4WD control
moduleInstrument cluster
•ABS
(ABS/
TCS) HU/
CM
•DSC HU/
CM————•Wiring harness D
•ABS (ABS/TCS)
HU/CM
•DSC HU/CM
—XXX•Wiring harness A
•PCM
X—XX•Wiring harness B
•TCM
XX—X•Wiring harness F
•4WD control
module
XXX—•Wiring harness G
•Instrument cluster
——XX•Wiring harness C
XX——•Wiring harness E
ModuleCommunication status
Malfunction location
PCM TCMABS (ABS/TCS) HU/CM
DSC HU/CM
4WD
control
module———•Wiring harness E
•Wiring harness F
•4WD control module
—XX•Wiring harness A
•PCM
X—X•Wiring harness B
•TCM
XX—•Wiring harness D
•ABS (ABS/TCS) HU/CM
•DSC HU/CM
——X•Wiring harness C
Page 885 of 909

U–22
ON-BOARD DIAGNOSTIC
FOREWORDA6E857001038201Outline
•When the customer reports a vehicle malfunction, verify the DTC, then diagnose the malfunction according to
following flowchart.
—If a DTC exists, diagnose according to the applicable DTC inspection (See U–22–2 DTC TABLE.)
—If a DTC exists, diagnose according to the applicable symptom troubleshooting (See U–26
TROUBLESHOOTING INDEX.)
Read/clear diagnostic results
•This function allows you to read or clear DTCs in the water heater unit.
DTCs Reading Procedure
1. Perform the necessary vehicle preparation and visual inspection.
2. Connect SST (WDS or equivalent) to the vehicle
DLC-2 16-pin connector located as shown in the
figure.
3. Retrieve DTCs using WDS or equivalent.
KOEO Self Test/Combustion Test
1. Connect the SST (WDS or equivalent) to the
vehicle DLC-2 16-pin connector located as shown
in the figure.
2. Select the “Supplemental Heater Test” in the
“Supplemental Heater Menu” of the “Guided
Diagnosis” function.
3. Perform the KOEO Self Test/Combustion Test.
Note
•If the water heater unit is operating, the
water heater unit will reject the test
command. Perform the DTC reading
procedure after the water heater unit stops
operating.
End Of Sie
ON-BOARD DIAGNOSTIC
Repair the malfunctioning part by following the
DTC inspection, referring to DTC TABLE.Connect the SST (WDS or equivalent).
Perform the KOEO Self Test/Combustion
Test.
Are any DTCs displayed?
Ye s
No Customer arrivesConfirm the malfunction symptom and troubleshoot
the water heater system for the applicable
malfunction, referring to the TROUBLESHOOTING
INDEX.
B6E0740TL01
DLC-2
A6E3970W002
DLC-2
A6E3970W002