Mazda CX 7. Manual - part 345

ON-BOARD DIAGNOSTIC [BCM]

09-02F–15

09-02F

End Of Sie

DTC B1873[BCM]

id0902f5832200

Diagnostic procedure

End Of Sie

DTC B1873

Hazard switch input circuit short to ground

DETECTION 
CONDITION

Short to GND in wiring harness between BCM and hazard warning switch

POSSIBLE 
CAUSE

• Short to GND in wiring harness between BCM terminal 3J and hazard warning switch terminal C

• Hazard warning switch malfunction

• BCM malfunction

STEP

INSPECTION

ACTION

1

INSPECT HAZARD WARNING SWITCH 
CONNECTOR

• Disconnect the hazard warning switch 

connector.

• Inspect the hazard warning switch connector 

terminals for poor connection (such as 
damaged/pulled-out pins, and corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 5.

No

Go to the next step.

2

INSPECT BCM CONNECTOR

• Disconnect the BCM connector.

• Inspect the BCM connector terminals for 

poor connection (such as damaged/pulled-
out pins, and corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 5.

No

Go to the next step.

3

INSPECT HAZARD WARNING SWITCH 
SIGNAL CIRCUIT FOR SHORT TO GND

• Inspect for continuity between BCM terminal 

3J (wiring harness-side) and body GND.

• Is there continuity?

Yes

Repair or replace the wiring harness for a possible short to 
GND, then go to Step 5.

No

Go to the next step.

4

INSPECT HAZARD WARNING SWITCH

• Inspect the hazard warning switch.

 (See 09-18-15 HAZARD WARNING 
SWITCH INSPECTION.)

• Is there any malfunction?

Yes

Replace the hazard warning switch, then go to the next 
step.
 (See 09-18-15 HAZARD WARNING SWITCH REMOVAL/
INSTALLATION.)

No

Go to the next step.

5

VERIFY TROUBLESHOOTING COMPLETED

• Make sure to reconnect all disconnected 

connectors.

• Clear the DTC from the BCM memory using 

the M-MDS.

• Perform the self-test.

 (See 09-02F-26 BCM SELF-TEST[BCM].)

• Is the same DTC present?

Yes

Replace the BCM.
 (See 09-40-1 BODY CONTROL MODULE (BCM) 
REMOVAL/INSTALLATION.)

No

DTC troubleshooting completed.

C

HAZARD WARNING SWITCH

BCM

3J

B

HAZARD WARNING SWITCH WIRING 

HARNESS-SIDE CONNECTOR

BCM WIRING HARNESS-SIDE  

CONNECTOR

3E

3G

3I

3K

3M

3O

3A

3C

3N

3L

3P

3H

3D

3B

3F

3J

3Q

3R

3S

3T

3U

3V

3W

3X

A

C

D

B

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ON-BOARD DIAGNOSTIC [BCM]

09-02F–16

DTC B2175[BCM]

id0902f5832400

Diagnostic procedure

End Of Sie

DTC B2175

A/C request switch circuit short to ground

DETECTION 
CONDITION

Short to GND in wiring harness between BCM and climate control unit (A/C ON request)

POSSIBLE 
CAUSE

• Short to GND in wiring harness between BCM terminal 3V and climate control unit terminal J

• Climate control unit malfunction

• BCM malfunction

STEP

INSPECTION

ACTION

1

INSPECT CLIMATE CONTROL UNIT 
CONNECTOR

• Disconnect the climate control unit 

connector.

• Inspect the climate control unit connector 

terminals for poor connection (such as 
damaged/pulled-out pins, and corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 5.

No

Go to the next step.

2

INSPECT BCM CONNECTOR

• Disconnect the BCM connector.

• Inspect the BCM connector terminals for 

poor connection (such as damaged/pulled-
out pins, and corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 5.

No

Go to the next step.

3

INSPECT CLIMATE CONTROL UNIT SIGNAL 
CIRCUIT FOR SHORT TO GND

• Inspect for continuity between BCM terminal 

3V (wiring harness-side) and body GND.

• Is there continuity?

Yes

Repair or replace the wiring harness for a possible short to 
GND, then go to Step 5.

No

Go to the next step.

4

INSPECT CLIMATE CONTROL UNIT

• Inspect the climate control unit.

 (See 07-40-16 CLIMATE CONTROL UNIT 
INSPECTION [MANUAL AIR 
CONDITIONER].)

• Is there any malfunction?

Yes

Replace the climate control unit, then go to the next step.
 (See 07-40-25 CLIMATE CONTROL UNIT REMOVAL 
[MANUAL AIR CONDITIONER], 07-40-26 CLIMATE 
CONTROL UNIT INSTALLATION [MANUAL AIR 
CONDITIONER].)

No

Go to the next step.

5

VERIFY TROUBLESHOOTING COMPLETED

• Make sure to reconnect all disconnected 

connectors.

• Clear the DTC from the BCM memory using 

the M-MDS.

• Perform the self-test.

 (See 09-02F-26 BCM SELF-TEST[BCM].)

• Is the same DTC present?

Yes

Replace the BCM.
 (See 09-40-1 BODY CONTROL MODULE (BCM) 
REMOVAL/INSTALLATION.)

No

DTC troubleshooting completed.

3V

J

CLIMATE CONTROL UNIT

BCM

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

S

R

U

V

W

X

CLIMATE CONTROL UNIT WIRING 

HARNESS-SIDE CONNECTOR

BCM WIRING HARNESS-SIDE  

CONNECTOR

Q

T

3E

3G

3I

3K

3M

3O

3A

3C

3N

3L

3P

3H

3D

3B

3F

3J

3Q

3R

3S

3T

3U

3V

3W

3X

1871-1U-06B(09-02F).fm  16 ページ  ２００６年３月１５日　水曜日　午前１１時４１分

ON-BOARD DIAGNOSTIC [BCM]

09-02F–17

09-02F

DTC B2218[BCM]

id0902f5839700

Diagnostic procedure

DTC B2218

Door lock switch circuit short to ground

DETECTION 
CONDITION

Short to GND in wiring harness between BCM and door lock switches

POSSIBLE 
CAUSE

• Short to GND in wiring harness between BCM terminal 5M and door lock switch (driver-side) terminal 

C

• Short to GND in wiring harness between BCM terminal 5N and door lock switch (passenger-side) 

terminal C

• Door lock switches malfunction

• BCM malfunction

STEP

INSPECTION

ACTION

1

INSPECT DOOR LOCK SWITCH 
CONNECTOR

• Disconnect the door lock switch connector.

• Inspect the door lock switch connector 

terminals for poor connection (such as 
damaged/pulled-out pins, and corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 5.

No

Go to the next step.

2

INSPECT BCM CONNECTOR

• Disconnect the BCM connector.

• Inspect the BCM connector terminals for 

poor connection (such as damaged/pulled-
out pins, and corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 5.

No

Go to the next step.

3

INSPECT DOOR LOCK SWITCH SIGNAL 
CIRCUIT FOR SHORT TO GND

• Inspect for continuity between BCM terminal 

5M, 5N (wiring harness-side) and body GND.

• Is there continuity?

Yes

Repair or replace the wiring harness for a possible short to 
GND, then go to Step 5.

No

Go to the next step.

4

INSPECT DOOR LOCK SWITCH

• Inspect the door lock switch.

 (See 09-14-8 DOOR LOCK SWITCH 
INSPECTION.)

• Is there any malfunction?

Yes

Replace the door lock switch, then go to the next step.
 (See 09-14-8 DOOR LOCK SWITCH REMOVAL/
INSTALLATION.)

No

Go to the next step.

BCM

5N

5M

LOCK

UNLOCK

LOCK

UNLOCK

DOOR LOCK SWITCH 
(DRIVER-SIDE)

DOOR LOCK SWITCH 
(PASSENGER-SIDE)

C

D

C

D

DOOR LOCK SWITCH WIRING 
HARNESS-SIDE CONNECTOR

BCM WIRING HARNESS-SIDE  

CONNECTOR

5Q

5K

5B

5E

5H

5AC

5N

5Z

5T

5W

5G

5D

5A

A

B

C

D

5O

5AA

5U

5X

5Y

5V

5S

5P

5M

5AD

5AB

5I

5F

5J

5C

5L

5R

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ON-BOARD DIAGNOSTIC [BCM]

09-02F–18

End Of Sie

DTC B2574[BCM]

id0902f5833100

5

VERIFY TROUBLESHOOTING COMPLETED

• Make sure to reconnect all disconnected 

connectors.

• Clear the DTC from the BCM memory using 

the M-MDS.

• Perform the self-test.

 (See 09-02F-26 BCM SELF-TEST[BCM].)

• Is the same DTC present?

Yes

Replace the BCM.
 (See 09-40-1 BODY CONTROL MODULE (BCM) 
REMOVAL/INSTALLATION.)

No

DTC troubleshooting completed.

STEP

INSPECTION

ACTION

DTC B2574

Driver door lock switch short to ground

DETECTION 
CONDITION

Short to GND in wiring harness between BCM and driver-side door lock-link switch

POSSIBLE 
CAUSE

• Short to GND in wiring harness between BCM terminal 5G and front door latch and lock actuator 

(driver-side) terminal E

• Front door latch and lock actuator (driver-side) malfunction

• BCM malfunction

FRONT DOOR LATCH AND LOCK 

ACTUATOR (DRIVER-SIDE)

5J

BCM

5G

F

B

E

FRONT DOOR LATCH AND LOCK 

ACTUATOR (DRIVER-SIDE) WIRING 

HARNESS-SIDE CONNECTOR

BCM WIRING HARNESS-SIDE  

CONNECTOR

5Q

5K

5B

5E

5H

5AC

5N

5Z

5T

5W

5G

5D

5A

5O

5AA

5U

5X

5Y

5V

5S

5P

5M

5AD

5AB

5I

5F

5J

5C

5L

5R

B

A

D

C

F

E

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