Mazda CX 7. Manual - part 202

ON-BOARD DIAGNOSTIC 

04-02–23

04-02

Diagnostic procedure

STEP

INSPECTION

ACTION

1

INSPECT PID TO VERIFY THAT WHEEL 
SPEED-SIGNALS ARE TRANSMITTED FROM 
ABS WHEEL- SPEED SENSOR USING M-
MDS

• Turn the ignition switch off.

• Connect the M-MDS to the DLC-2.

• Select the following PIDs using the M-MDS:

WSPD_LF
WSPD_LR
WSPD_RF
WSPD_RR

• Drive the vehicle.

• Verify that the wheel speed-signals are 

transmitted from each ABS wheel-speed 
sensor.

• Are the wheel-speed signals transmitted?

Yes

Go to Step 3.

No

Go to the next step.

A
B

B

A

A

B

G

M
O

H

F
E

L

I

B

A

RF 
ABS WHEEL-SPEED 
SENSOR

LF 
ABS WHEEL-SPEED 
SENSOR

RR 
ABS WHEEL-SPEED 
SENSOR

LR 
ABS WHEEL-SPEED 
SENSOR

DSC  HU/CM

A

B

A

B

ABS WHEEL-SPEED SENSOR WIRING HARNESS-SIDE CONNECTOR

FRONT

REAR

A

B

C

D

F

I

L

O

R

U

X

E

H

Q

T

W

Z

G

J

M

P

S

V

Y

K

N

AA

AB

AC

AD

AE

AF

AG

AH

AI

AJ

AK

AL

AM

AN

AO

AP

AQ

AR

AS

AT

DSC HU/CM WIRING HARNESS-SIDE CONNECTOR

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ON-BOARD DIAGNOSTIC 

04-02–24

End Of Sie

DTC C1279, C1280, C1281, C1282, C1951, C1952, C1959, C2768

id040200801700

2

INSPECT FOR OPEN CIRCUIT IN WIRING 
HARNESS BETWEEN DSC HU/CM AND ABS 
WHEEL-SPEED SENSOR

• Turn the ignition switch off.

• Disconnect the DSC HU/CM connector and 

ABS wheel-speed sensor.

• Inspect for continuity in the wiring harness 

between the following ABS wheel-speed 
sensor connectors on the vehicle wiring 
harness-side and DSC HU/CM connectors.

— RF ABS wheel-speed sensor: M— A

— RF ABS wheel-speed sensor: O— B

— LF ABS wheel-speed sensor: F— A

— LF ABS wheel-speed sensor: E— B

— RR ABS wheel-speed sensor: I— A

— RR ABS wheel-speed sensor: L— B

— LR ABS wheel-speed sensor: G— A

— LR ABS wheel-speed sensor: H— B

• Is there continuity?

Yes

Replace the ABS wheel-speed sensor, then go to the next 
step.
 (See 04-15-11 FRONT ABS WHEEL-SPEED SENSOR 
REMOVAL/INSTALLATION.)
 (See 04-15-13 REAR ABS WHEEL-SPEED SENSOR 
REMOVAL/INSTALLATION[2WD].)
 (See 04-15-13 REAR ABS WHEEL-SPEED SENSOR 
REMOVAL/INSTALLATION[AWD].)

No

Repair or replace the wiring harness, then go to the next 
step.

3

VERIFY THAT THE SAME DTC IS NOT 
PRESENT

• Clear the DTCs from the memory.

 (See 04-02-3 ON-BOARD DIAGNOSIS.)

• Start the engine and drive the vehicle at 10 

km/h {6.2 mph} or more.

• Are the same DTCs present?

Yes

Repeat the inspection from Step 1.
If the malfunction recurs, replace the DSC HU/CM, then go 
to the next step.
 (See 04-15-6 DSC HU/CM REMOVAL/INSTALLATION.)

No

Go to the next step.

4

VERIFY THAT NO OTHER DTCS ARE 
PRESENT

• Are any other DTCs output?

Yes

Go to the applicable DTC inspection.
(See 04-02-3 ON-BOARD DIAGNOSIS.)

No

DTC troubleshooting completed.

STEP

INSPECTION

ACTION

DTC

C1279, C1280, C1281, C1282, C1951, 
C1952, C1959, C2768 

Combined sensor system

DETECTION 

CONDITION

• C1279

— The yaw rate value from the combined sensor (yaw rate part) exceeds specification while the vehicle 

is stopped or while accelerating from a standstill.

• C1280

— The difference between the yaw rate value calculated by each sensor and the yaw rate value from 

the combined sensor (yaw rate part) exceeds specification.

• C1281

— The difference between the lateral-G value calculated by each sensor and the lateral-G value from 

the combined sensor (lateral-G part) exceeds specification.

• C1282

— Specified signal pattern from combined sensor has not output after the ignition switch is turned to the 

ON position.

• C1951

— The monitor voltage from the combined sensor (lateral-G part) is not within specification.

• C1952

— The monitor voltage from the combined sensor (yaw rate part) is not within specification.

• C1959

— The lateral-G value from the combined sensor (lateral-G part) exceeds specification.

• C2768

— There is an abnormality in the signal from the combined sensor (yaw rate part).

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ON-BOARD DIAGNOSTIC 

04-02–25

04-02

POSSIBLE 

CAUSE

• Open circuit in the wiring harness between ignition switch and combined sensor terminal E or short 

circuit to ground

• Open circuit in the wiring harness between DSC HU/CM terminal Y and combined sensor terminal F or 

short circuit to ground

• Open circuit in the wiring harness between DSC HU/CM terminal AB and combined sensor terminal C 

or short circuit to ground

• Open circuit in the wiring harness between DSC HU/CM terminal AE and combined sensor terminal A 

or short circuit to ground

• Open circuit in the wiring harness between DSC HU/CM terminal AA and combined sensor terminal B 

or short circuit to ground

• Open circuit in the wiring harness between DSC HU/CM terminal AI and combined sensor terminal D

• Combined sensor malfunction

• Poor connection at connectors (female terminal)

DSC  HU/CM

A

B

C

D

F

I

L

O

R

U

X

E

H

Q

T

W

Z

G

J

M

P

S

V

Y

K

N

AA

AB

AC

AD

AE

AF

AG

AH

AI

AJ

AK

AL

AM

AN

AO

AP

AQ

AR

AS

AT

DSC HU/CM WIRING HARNESS-SIDE CONNECTOR

E
F

C
A

D

B

Y

AB

AE

AI

AA

COMBINED SENSOR

IG 1

A

B

C

D

F

E

COMBINED SENSOR WIRING HARNESS-SIDE CONNECTOR

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ON-BOARD DIAGNOSTIC 

04-02–26

Diagnostic procedure

STEP

INSPECTION

ACTION

1

INSPECT COMBINED SENSOR POWER 
SUPPLY FOR OPEN CIRCUIT

• Turn the ignition switch to the ON position 

(engine off).

• Measure voltage between combined sensor 

terminal E (harness-side) and ground.

• Is the voltage B+?

Yes

Go to the next step.

No

Repair or replace the wiring harness for open circuit 
between combined sensor terminal E and ignition switch, 
then go to Step 12.

2

INSPECT COMBINED SENSOR GROUND 
FOR OPEN CIRCUIT

• Turn the ignition switch off.

• Disconnect DSC HU/CM and combined 

sensor connectors.

• Inspect for continuity between DSC HU/CM 

terminal Y (harness-side) and combined 
sensor terminal F (harness-side).

• Is there continuity?

Yes

Go to the next step.

No

Repair or replace the wiring harness for open circuit 
between DSC HU/CM terminal Y and combined sensor 
terminal F, then go to Step 12.

3

INSPECT COMBINED SENSOR (YAW RATE 
PART) SIGNAL FOR OPEN CIRCUIT

• Inspect for continuity between DSC HU/CM 

terminal AA (harness-side) and combined 
sensor terminal B (harness-side).

• Is there continuity?

Yes

Go to the next step.

No

Repair or replace the wiring harness for open circuit 
between DSC HU/CM terminal AA and combined sensor 
terminal B, then go to Step 12.

4

INSPECT COMBINED SENSOR (YAW RATE 
PART) SIGNAL FOR SHORT TO GROUND

• Turn the ignition switch off.

• Inspect for continuity between DSC HU/CM 

terminal AA (harness-side) and ground.

• Is there continuity?

Yes

Repair or replace the wiring harness for short to ground 
between DSC HU/CM terminal AA and combined sensor 
terminal B, then go to Step 12.

No

Go to the next step.

5

INSPECT COMBINED SENSOR (LATERAL-G 
PART) SIGNAL FOR OPEN CIRCUIT

• Inspect for continuity between DSC HU/CM 

terminal AI (harness-side) and combined 
sensor terminal D (harness-side).

• Is there continuity?

Yes

Go to the next step.

No

Repair or replace the wiring harness for open circuit 
between DSC HU/CM terminal AI and combined sensor 
terminal D, then go to Step 12.

6

INSPECT COMBINED SENSOR (LATERAL-G 
PART) SIGNAL FOR SHORT TO GROUND

• Turn the ignition switch off.

• Inspect for continuity between DSC HU/CM 

terminal AI (harness-side) and ground.

• Is there continuity?

Yes

Repair or replace the wiring harness for short to ground 
between DSC HU/CM terminal AI and combined sensor 
terminal D, then go to Step 12.

No

Go to the next step.

7

INSPECT REFERENCE SIGNAL FOR OPEN 
CIRCUIT

• Turn the ignition switch off.

• Inspect for continuity between DSC HU/CM 

terminal AE (harness-side) and combined 
sensor terminal A (harness-side).

• Is there continuity?

Yes

Go to the next step.

No

Repair or replace the wiring harness for open circuit 
between DSC HU/CM terminal AE and combined sensor 
terminal A, then go to Step 12.

8

INSPECT REFERENCE SIGNAL FOR SHORT 
TO GROUND

• Turn the ignition switch off.

• Inspect for continuity between DSC HU/CM 

terminal AE (harness-side) and ground.

• Is there continuity?

Yes

Repair or replace the wiring harness for short to ground 
between DSC HU/CM terminal AE and combined sensor 
terminal A, then go to Step 12.

No

Go to the next step.

9

INSPECT TEST SIGNAL FOR OPEN CIRCUIT

• Turn the ignition switch off.

• Inspect for continuity between DSC HU/CM 

terminal AB (harness-side) and combined 
sensor terminal C (harness-side).

• Is there continuity?

Yes

Go to the next step.

No

Repair or replace the wiring harness for open circuit 
between DSC HU/CM terminal AB and combined sensor 
terminal C, then go to Step 12.

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