Mazda CX-9 Grand Touring. Manual — part 125

DIAGNOSTIC PROCEDURE

DTC U1901 [DSC/RSC] DIAGNOSTIC PROCEDURE

STEP

INSPECTION

ACTION

1

INSPECT COMBINED SENSOR SIGNAL
(CAN2 LINE) FOR OPEN CIRCUIT



Disconnect the DSC/RSC HU/CM
connectors.



Disconnect the combined sensor connectors.



Inspect for continuity between the
DSC/RSC HU/CM connectors (vehicle
harness-side) and the following combined
sensor connector terminals (vehicle harness-
side):



Combined sensor (CAN2_L): M-C



Combined sensor (CAN2_H): P-D



Is there continuity?

Yes Go to the next step.

No

Repair or replace the wiring harness, then

go to Step 4.

2

INSPECT COMBINED SENSOR SIGNAL
(CAN2 LINE) FOR SHORT CIRCUIT



Inspect for continuity between the following
DSC/RSC HU/CM connector terminals

Yes

Repair or replace the wiring harness, then
go to Step 4.

2008 Mazda CX-9 Grand Touring

2008 BRAKES On-Board Diagnostic (DSC/RSC) - Mazda CX-9

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(vehicle harness-side) and body ground:



Combined sensor (CAN2_L): M



Combined sensor (CAN2_H): P



Is there continuity?

No

Go to the next step.

3

INSPECT THE COMBINED SENSOR



Reconnect all disconnected connectors.
Inspect the combined sensor.

(See COMBINED SENSOR
INSPECTION .)



Is the combined sensor normal?

Yes Go to the next step.

No

Replace the combined sensor, then go to

the next step.

(See COMBINED SENSOR

REMOVAL/INSTALLATION .)

4

VERIFY THAT THE SAME DTC IS NOT
PRESENT



Clear the DTCs from the memory.

(See ON-BOARD DIAGNOSTIC
[DSC/RSC].)



Are the same DTCs present?

Yes

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

No

Go to the next step.

5

VERIFY THAT NO OTHER DTCS ARE
PRESENT



Are any other DTCs output?

Yes

Go to the applicable DTC inspection.
(See ON-BOARD DIAGNOSTIC
[DSC/RSC].)

No

DTC troubleshooting completed.

2008 Mazda CX-9 Grand Touring

2008 BRAKES On-Board Diagnostic (DSC/RSC) - Mazda CX-9

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2008 BRAKES

Symptom Troubleshooting (DSC/RSC) - Mazda CX-9

SYSTEM WIRING DIAGRAM [DSC/RSC]

Fig. 1: Brakes System Wiring Diagram (DSC/RSC)
Courtesy of MAZDA MOTORS CORP.

FOREWORD [DSC/RSC]



Before performing the steps in Symptom Troubleshooting, perform the On-board Diagnostic Inspection.
To check the DTC, follow the DTC Inspection steps. (See ON-BOARD DIAGNOSIS [DSC/RSC] .)

PRECAUTION [DSC/RSC]

1. The ABS warning light and/or BRAKE system warning light and/or DSC indicator light and/or TCS OFF

light illuminate even when the system is normal.

PRECAUTION CHART [DSC/RSC]

Warning lights
that may
illuminate
and/or flash

Condition under which the
light may illuminate

Conditions under
which the light will
go out

ABS, EBD, TCS, DSC, and
RSC control

Under any of the following
conditions:



When the front wheels are
jacked up, stuck, or placed
on a chassis roller, and
only the front wheel ABS



ABS: Disables control.



EBD:

1. Disable control, in cases

where the light may
illuminate, only when

2008 Mazda CX-9 Grand Touring

2008 BRAKES Symptom Troubleshooting (DSC/RSC) - Mazda CX-9

2008 Mazda CX-9 Grand Touring

2008 BRAKES Symptom Troubleshooting (DSC/RSC) - Mazda CX-9

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2. Precautions during servicing of DSC/RSC

The DSC/RSC is composed of electrical and mechanical parts. It is necessary to categorize malfunctions
as being either electrical or hydraulic when performing troubleshooting.

1. Malfunction in electrical system



The control module has an on-board diagnostic function. With this function, the ABS
warning light and/or BRAKE system warning light and/or DSC indicator light and/or TCS
OFF light will illuminate when there is a problem in the electrical system.

Also, past and present malfunctions are in the control module. This function can find
malfunctions that do not occur during periodic inspections. Connect the M-MDS to the DLC-
2, the stored malfunctions will be displayed in the order of occurrence. To find out the causes
of DSC/RSC malfunctions, use these on-board diagnostic results.



If a malfunction occurred in the past but is now normal, the cause is likely a temporary poor
connection of the wiring harness.

The control module usually operates normally. Be careful when searching for the cause of
malfunction.



ABS
warning
light



BRAKE
system
warning
light



DSC
indicator
light



TCS OFF
light

wheel speed sensors are
spun for 20 s or more.

After turning
ignition switch off,
vehicle is driven at
speed greater than
10 km/h {6.2 mph}
and normal
operation is
confirmed.

DSC/RSC HU/CM
detects that wheel speed
sensors determine that
two or more wheels are
malfunctioning.

2. Enables control, if wheel

speed sensors determine
three or more wheels are
functioning correctly.



TCS: Disables control.



DSC: Disables control.



RSC: Disables control.

Parking brake is not fully
released while driving.

Brake drag.

Sudden
acceleration/deceleration.

Left/right or front/rear tires are
different. (Size, radius, tire
pressure, or wear is other than
that listed on tire label.)

Battery voltage at DSC/RSC
HU/CM ignition terminal drops
below approx. 10 V.

Battery voltage rises
above approx. 10
V.

ABS: Disables control.
EBD: Enables control.
TCS: Disables control.
DSC: Disables control.
RSC: Disables control.



Brake
system
warning
light

Brake fluid amount is low.

Brake fluid level
lower than
recommended
amount.

ABS: Enables control.
EBD: Enables control.
TCS: Enables control.
DSC: Disables control.
RSC: Disables control.

2008 Mazda CX-9 Grand Touring

2008 BRAKES Symptom Troubleshooting (DSC/RSC) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 9:41:34 AM

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© 2005 Mitchell Repair Information Company, LLC.