Mazda CX 7. Manual - part 338

ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]

09-02D–9

09-02D

2007 Mazda CX-7 Workshop Manual (1871–1U–06B)

Revised 12/2006 (Ref. No. R215/06) 

TCM

1. Inspect the display of DTC U0100, U0121, U0140 and/or U0415 using the M-MDS. (See 09-02D-7 DTC 

TABLE[MULTIPLEX COMMUNICATION SYSTEM].)

2. Referring to the following table, determine the malfunctioning part of the CAN system.

×: Normal

— : Communication error

DSC HU/CM

1. Inspect the display of DTC U0100, U0101, U0114, U0140, U1900 and/or U2023 using the M-MDS. (See 09-

02D-7 DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].)

Caution

• DTC U2023 may not be cleared during engine starting even if DTC clearing is done using the M-

MDS. When clearing DTC U2023, execute with the ignition switch in the ON position (Engine off).

Note

• You may want to check which unit is malfunctioning according to Freeze Frame Data. "Electrical" > "IC 

Service Function" > "Freeze Frame Data".This function is supported on IDS, not PDS.

2. Referring to the following table, determine the malfunctioning part of the CAN system.

×: Normal

— : Communication error

Module

Communication status

Malfunction location

PCM

DSC HU/CM

Instrument cluster

TCM

— — — 

• Wiring harness B

• TCM

— 

×

×

• Wiring harness A

• PCM

×

— 

×

• Wiring harness D

• DSC HU/CM

×

— — 

• Wiring harness C

×

×

— 

• Wiring harness E

• BCM

• Wiring harness F

• Wiring harness H

• Wiring harness J

• Wiring harness K

• Wiring harness M

• Instrument cluster

Module

Communication status

Malfunction location

PCM

TCM

AWD control 

module

BCM

DSC HU/CM

— — — — 

• Wiring harness D

• DSC HU/CM

— 

×

×

×

• Wiring harness A

• PCM

×

— 

×

×

• Wiring harness B

• TCM

— — 

×

×

• Wiring harness C

×

×

— 

×

• Wiring harness G

• AWD control module

×

×

— — 

• Wiring harness E

• BCM

• Wiring harness F

×

×

×

— 

• Wiring harness H

• Wiring harness J

• BCM

ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]

09-02D–10

2007 Mazda CX-7 Workshop Manual (1871–1U–06B)

AWD Control Module

1. Inspect the display of DTC U0100, U0101, U0121 and/or U0155 using the M-MDS. (See 09-02D-7 DTC 

TABLE[MULTIPLEX COMMUNICATION SYSTEM].)

2. Referring to the following table, determine the malfunctioning part of the CAN system.

×: Normal

— : Communication error

BCM

Note

• There is no DTC in the BCM that determines signal quality between it and the other module. Due to this, 

determine the malfunction location using the DTC on the other module side. 

1. Referring to the following table, determine the malfunctioning part of the CAN system.

×: Normal

— : Communication error

Module

Communication status

Malfunction location

PCM

TCM

DSC HU/CM

Instrument 

cluster

AWD Control 
Module

— — — — 

• Wiring harness G

• AWD Control Module

— 

×

×

×

• Wiring harness A

• PCM

×

— 

×

×

• Wiring harness B

• TCM

— — 

×

×

• Wiring harness C

×

×

— 

×

• Wiring harness D

• DSC HU/CM

— — — 

×

• Wiring harness E

• BCM

• Wiring harness F

×

×

×

— 

• Wiring harness H

• Wiring harness J

• BCM

• Wiring harness K

• Wiring harness M

• Instrument cluster

Module

Communication status

Malfunction location

DSC HU/CM

Keyless control 

module

Instrument cluster

BCM

— — — 

• BCM

— 

×

×

• Wiring harness D

• Wiring harness E

• BCM

• Wiring harness F

• Wiring harness H

• Wiring harness J

• DSC HU/CM

×

— 

×

• Wiring harness L

• Keyless control module

×

— — 

• Wiring harness K

×

×

— 

• Wiring harness M

• Instrument cluster

ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]

09-02D–11

09-02D

2007 Mazda CX-7 Workshop Manual (1871–1U–06B)

Revised 12/2006 (Ref. No. R215/06) 

SAS Control Module

1. Inspect the display of DTC U0155 using the M-MDS.

(See 09-02D-7 DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].)

2. Referring to the following table, determine the malfunctioning part of the CAN system.

×: Normal

— : Communication error

Keyless Control Module

1. Inspect the display of DTC U0100, U0140, U0323 and/or U2023 using the M-MDS.

(See 09-02D-7 DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].)

Caution

• DTC U2023 may not be cleared during engine starting even if DTC clearing is done using the M-

MDS. When clearing DTC U2023, execute with the ignition switch in the ON position (Engine off).

Note

• You may want to check which unit is malfunctioning according to Freeze Frame Data. "Electrical" > "IC 

Service Function" > "Freeze Frame Data".This function is supported on IDS, not PDS.

2. Referring to the following table, determine the malfunctioning part of the CAN system.

×: Normal

— : Communication error

Module

Communication status

Malfunction location

Instrument cluster

SAS control module

— 

• SAS control module

• Wiring harness I

• Wiring harness J

• BCM

• Wiring harness K

• Wiring harness M

• Instrument cluster

Module

Communication status

Malfunction location

PCM

BCM

Instrument cluster

Keyless control 
module

— — — 

• Wiring harness L

• Keyless control module

— 

×

×

• Wiring harness A

• Wiring harness C

• Wiring harness E

• BCM

• Wiring harness F

• Wiring harness H

• Wiring harness J

• PCM

— — 

×

• Wiring harness K

• BCM

×

— 

×

• BCM

×

×

— 

• Wiring harness M

• Instrument cluster

ON-BOARD DIAGNOSTIC [MULTIPLEX COMMUNICATION SYSTEM]

09-02D–12

2007 Mazda CX-7 Workshop Manual (1871–1U–06B)

Instrument Cluster

1. Inspect the display of DTC U0100, U0101, U0114, U0121, U0140, U0151 and/or U0214 using the M-MDS. 

(See 09-02D-7 DTC TABLE[MULTIPLEX COMMUNICATION SYSTEM].)

2. Referring to the following table, determine the malfunctioning part of the CAN system.

×: Normal

— : Communication error

Note

• There is no DTC in the instrument cluster that determines signal quality between it and the information 

display. Due to this, determine the malfunction location using the DTC on the information display.

3. Inspect the display of DTC U0164 using the M-MDS. (See 09-02D-7 DTC TABLE[MULTIPLEX 

COMMUNICATION SYSTEM].)

4. Referring to the following table, determine the malfunctioning part of the CAN system.

×: Normal

— : Communication error

Module

Communication status

Malfunction location

PCM

TCM

DSC HU/

CM

AWD 

control 

module

SAS 

control 

module

BCM

Keyless 

control 

module

Instrument 
cluster

— — — — — — — 

• Wiring harness M

• Instrument cluster

— 

×

×

×

×

×

×

• Wiring harness A

• PCM

— — 

×

×

×

×

×

• Wiring harness C

×

— 

×

×

×

×

×

• Wiring harness B

• TCM

— — — 

×

×

×

×

• Wiring harness E

• BCM

• Wiring harness F

×

×

— 

×

×

×

×

• Wiring harness D

• DSC HU/CM

— — — — 

×

×

×

• Wiring harness H

×

×

×

— 

×

×

×

• Wiring harness G

• AWD control module

— — — — — 

×

×

• Wiring harness J

• BCM

×

×

×

×

— 

×

×

• Wiring harness I

• SAS control module

— — — — — — 

×

• Wiring harness K

• BCM

×

×

×

×

×

— 

×

• BCM

×

×

×

×

×

×

— 

• Wiring harness L

• Keyless control module

Module

Communication status

Malfunction location

Climate control unit

Information display

Instrument 
cluster

— — 

• Wiring harness N

• Instrument cluster

— 

×

• Wiring harness O

• Climate control unit

×

— 

• Wiring harness Q

• Wiring harness S

• Information display