Mazda 6. Manual - part 256

P–80

ON-BOARD DIAGNOSTIC (DYNAMIC STABILITY CONTROL) 

Diagnostic procedure

End Of Sie

DTC C1125

A6E697367650W10

Diagnostic procedure

End Of Sie

STEP

INSPECTION

ACTION

1

CHECK FOR PCM FOR DTCs

• Turn ignition key to OFF.

• Connect WDS or equivalent to DLC-2

• Turn ignition key to ON (engine OFF).

• Is DTC for engine control system obtained?

Yes

Follow inspection procedures for engine control system.

No

Go to next step.

2

MONITOR CAN SIGNAL

• Access PID RPM and TP using WDS or 

equivalentI.

• Are engine speed and throttle position within 

specification?

Yes

Go to next step.

No

Follow inspection procedures for engine control system.

3

VERIFY TROUBLESHOOTING COMPLETED

• Make sure to reconnect all disconnected 

connectors.

• Clear DTC from memory.

(See 

P–46 Clearing DTCs Procedures

)

• Start engine.

• Is same DTC present?

Yes

Replace DSC HU/CM, then go to next step.

No

Go to next step.

DTC

C1125

Brake fluid level sensor

DETECTION 

CONDITION

• Brake fluid level remains low for 5 seconds or more.

POSSIBLE 

CAUSE

• Decrease in amount of brake fluid

• Malfunction of brake fluid level sensor

STEP

INSPECTION

ACTION

1

CHECK FOR CAN FOR DTCs

• Is any of DTC U1900 and/or U2516 has also 

been stored?

Yes

Follow inspection procedures for CAN system.
(See 

T–144 DTC U0073, U1900, U2516

)

No

Go to next step.

2

INSPECT BRAKE FLUID LEVEL

• Inspect brake fluid level.

• Is it okay?

Yes

Go to next step.

No

Add brake fluid to specified level, then go to Step 3.

3

INSPECT BRAKE FLUID LEVEL SENSOR

• Turn ignition key to OFF.

• Disconnect brake fluid level sensor 

connector.

• Measure resistance between brake fluid 

level sensor terminals.
— Brake fluid level above MIN: resistance 

about 500 ohms

— Brake fluid level below MIN: resistance 

within 0—1 ohm

• Is it okay?

Yes

Go to next step.

No

Repair brake fluid level sensor, then go to Next step.

4

VERIFY TROUBLESHOOTING COMPLETED

• Make sure to reconnected all disconnected 

connectors.

• Clear DTC from memory.

(See 

P–46 Clearing DTCs Procedures

)

• Is same DTC present?

Yes

Replace DSC HU/CM, then go to next step.

No

Go to next step.

5

VERIFY AFTER REPAIR PROCEDURE

• Is there any other DTC present?

Yes

Go to applicable DTC inspection.

No

Troubleshooting completed.

ON-BOARD DIAGNOSTIC (DYNAMIC STABILITY CONTROL) 

P–81

P

DTC C1140

A6E697367650W11

Diagnostic procedure

End Of Sie

DTC C1145, C1155, C1165, C1175

A6E697367650W12

Caution

• When attaching the tester lead to the DSC HU/CM connector the SST (49 G066 004) must be used. 

DTC

C1140

DSC HU/CM (pump)

DETECTION 

CONDITION

Right front and left rear wheels, or left front and right rear wheel-lock is detected during DSC operation.

POSSIBLE 

CAUSE

Stuck pump motor in DSC HU/CM

STEP

INSPECTION

ACTION

1

INSPECT DSC HU/CM OPERATION

• Perform DSC HU/CM system inspection.

(See 

P–35 DSC SYSTEM INSPECTION

)

• Is it okay?

Yes

Go to next step.

No

Replace DSC HU/CM, then go to Step 4.

2

INSPECT CONVENTIONAL BRAKE 
OPERATION

• Inspect brake fluid level.

• Start engine.

• Perform a road test to verify conventional 

vehicle braking performance.

• Is there any concern.

Yes

Inspect conventional brake line, then go to Step 4.

No

Go to next step.

3

INSPECT REAR BRAKE DRAGGING

• Turn ignition key to OFF.

• Jack-up vehicle and support it with safety 

stand.

• Release parking brake.

• Turn rear wheel by hand and inspect for rear 

brake drag.

• Is rear brake dragging?

Yes

Repair parking brake system, then go to next step.

No

Go to next step.

4

VERIFY TROUBLESHOOTING COMPLETED

• Clear DTC from memory.

(See 

P–46 Clearing DTCs Procedures

)

• Start engine and drive vehicle at 10 km/h 

{6.2 mph} or above at least one minute.

• Gradually slow down vehicle and stop.

• Is same DTC present?

Yes

Replace DSC HU/CM, then go to next step.

No

Go to next step.

5

VERIFY AFTER REPAIR PROCEDURE

• Is there any other DTC present?

Yes

Go to applicable DTC inspection.

No

Troubleshooting completed.

DTC

C1145
C1155
C1165
C1175

RF wheel-speed sensor
LF wheel-speed sensor
RR wheel-speed sensor
LR wheel-speed sensor

DETECTION 

CONDITION

• Abnormal input is detected.

POSSIBLE 

CAUSE

• Open or short to ground circuit in harness between DSC HU/CM terminal and wheel-speed sensor(s) 

terminal below
— DSC HU/CM terminal M—RF wheel-speed sensor terminal A
— DSC HU/CM terminal I—RF wheel-speed sensor terminal B
— DSC HU/CM terminal F—LF wheel-speed sensor terminal A
— DSC HU/CM terminal J—LF wheel-speed sensor terminal B
— DSC HU/CM terminal K—RR wheel-speed sensor terminal A
— DSC HU/CM terminal H—RR wheel-speed sensor terminal B
— DSC HU/CM terminal Q—LR wheel-speed sensor terminal A
— DSC HU/CM terminal N—LR wheel-speed sensor terminal B

• Malfunction of wheel-speed sensor(s)

P–82

ON-BOARD DIAGNOSTIC (DYNAMIC STABILITY CONTROL) 

Diagnostic procedure

STEP

INSPECTION

ACTION

1

INSPECT WHEEL-SPEED SENSOR CIRCUIT 
FOR OPEN CIRCUIT

• Turn ignition key to OFF.

• Disconnect DSC HU/CM connector.

• Measure resistance between suspected 

sensor terminals of DSC HU/CM connector 
(harness side).
— RF wheel-speed sensor: M—I
— LF wheel-speed sensor: F—J
— RR wheel-speed sensor: K—H
— LR wheel-speed sensor: Q—N

• Is resistance within 1.3—1.7 kilohm?

Yes

Go to next step.

No

Go to Step 3.

ON-BOARD DIAGNOSTIC (DYNAMIC STABILITY CONTROL) 

P–83

P

End Of Sie

DTC C1148, C1158, C1168, C1178, C1233, C1234, C1235, C1236

A6E697367650W13

2

INSPECT WHEEL-SPEED SENSOR CIRCUIT 
FOR SHORT TO GROUND

• Turn ignition key to OFF.

• Inspect continuity between suspected sensor 

terminal(s) of DSC HU/CM connector 
(harness side) and ground(s).
— RF wheel-speed sensor (+): M
— RF wheel-speed sensor (–): I
— LF wheel-speed sensor (+): F
— LF wheel-speed sensor (–): J
— RR wheel-speed sensor (+): K
— RR wheel-speed sensor (–): H
— LR wheel-speed sensor (+): Q
— LR wheel-speed sensor (–): N

• Is there continuity?

Yes

Repair or replace harness for short to ground circuit 
between DSC HU/CM and wheel-speed sensor(s), then go 
to Step 5.

No

Go to Step 5.

3

INSPECT WHEEL-SPEED SENSOR

• Turn ignition key to OFF.

• Disconnect suspected sensor connector(s) 

and inspect resistance between sensor 
terminals (part side).

• Is resistance within 1.3—1.7 kilohm?

Yes

Go to next step.

No

Replace wheel-speed sensor, then go to Step 5.

4

INSPECT DSC HU/CM TO WHEEL-SPEED 
SENSOR CIRCUIT FOR OPEN CIRCUIT

• Inspect continuity between suspected sensor 

terminal(s) of DSC HU/CM connector 
(harness side) and wheel-speed sensor 
connector. (vehicle harness side)
— RF wheel-speed sensor (+): M—A
— RF wheel-speed sensor (–): I—B
— LF wheel-speed sensor (+): F—A
— LF wheel-speed sensor (–): J—B
— RR wheel-speed sensor (+): K—A
— RR wheel-speed sensor (–): H—B
— LR wheel-speed sensor (+): Q—A
— LR wheel-speed sensor (–): N—B

• Is there continuity?

Yes

Repair or replace poor connections of DSC HU/CM 
connector and/or wheel-speed sensor connector(s), then go 
to next step.

No

Repair or replace harness for open circuits between DSC 
HU/CM and wheel-speed sensor(s), then go to next step.

5

VERIFY TROUBLESHOOTING COMPLETED

• Make sure to reconnect all disconnected 

connectors.

• Clear DTC from memory.

(See 

P–46 Clearing DTCs Procedures

)

• Is same DTC present?

Yes

Replace DSC HU/CM, then go to next step.

No

Go to next step.

6

VERIFY AFTER REPAIR PROCEDURE

• Is there any other DTC present?

Yes

Go to applicable DTC inspection.

No

Troubleshooting completed.

STEP

INSPECTION

ACTION

DTC

C1148, C1234
C1158, C1233
C1168, C1235
C1178, C1236

RF wheel-speed sensor/sensor rotor
LF wheel-speed sensor/sensor rotor
RR wheel-speed sensor/sensor rotor
LR wheel-speed sensor/sensor rotor

DETECTION 

CONDITION

• C1148, C1158, C1168, C1178: 

— Abnormal sensor output is detected on any of four vehicle wheels when the vehicle goes from start 

to a speed of 10 km/h {6.2 mph}.

— Greater than specified amount of ABS demand occurs from front wheel sensors when vehicle is 

started.

• C1234, C1233, C1235, C1236: 

— Abnormal sensor output due to chipping of sensor rotor teeth, etc. is detected.
— ABS control operates for 60 seconds or more.

POSSIBLE 

CAUSE

• Short to ground circuit of wheel-speed sensor(s) circuit

• Malfunction of wheel-speed sensor(s)

• Damaged sensor rotor(s)

• Incorrect clearance between wheel-speed sensor and sensor rotor

• Poor installation of wheel speed sensor and/or sensor rotor (If the sensor rotor is installed twisted, it 

may cause output of abnormal wave form at high speeds).

• DSC HU/CM internal damage (Solenoid valve malfunction, pump motor malfunction, or pipe clogging)