On-Board Diagnostic System Function; Malfunction Detection Function; Memory Function; Fail-Safe Function - Mazda CX-9 2007 Service Highlights

ON-BOARD DIAGNOSTIC SYSTEM FUNCTION

Malfunction Detection Function

• The malfunction detection function detects malfunctions in the input/output signal system of the dynamic
stability control (DSC)/roll stability control (RSC) hydraulic unit (HU)/control module (CM) when the ignition
switch is at the switch on (ON) position.
• When the DSC/RSC HU/CM are started up, the following malfunction detections are performed.
— The antilock brake system (ABS) and brake system warning lights, traction control system (TCS) switch off
(OFF) and DSC indicator lights illuminate for approx. 3 s when the ignition switch is turned to the ON
position. At the same time, the fail-safe relay is operated, and the input/output signals of each part is
monitored for malfunction diagnosis. After starting to drive, the first time the vehicle speed is approx. 15
km/h {9.3 mph} or more the pump motor is operated and malfunction diagnosis is performed again.
• When malfunctions are detected, the corresponding lights are illuminated to alert the driver. Using the external
tester communication function, DTCs can be output through the HS_CAN_H and HS_CAN_L of the DLC-2. At
the same time, malfunction detection results are sent to the memory and fail-safe functions.

Memory Function

• The memory function stores DTCs of malfunctions in input/output signal systems. With this function, once a
DTC is stored it is not cleared after the ignition switch has been turned off (LOCK position), even if the
malfunctioning signal system has returned to normal.
• Since the DSC/RSC HU/CM has a built-in non-volatile memory, DTCs are not cleared even if the battery is
removed. Therefore, it is necessary to clear the memory after performing repairs. Refer to the Workshop
Manual for the DTC clearing procedure.

Fail-safe Function

• When the malfunction detection function determines a malfunction, each light illuminates to advise the driver.
At this time, the fail-safe function controls the ABS, electronic brakeforce distribution (EBD), TCS, DSC and
RSC as shown in the fail-safe function table.
Warning
• If EBD control is suspended the rear wheels could lock-up before the front wheels. If this occurs,
the vehicle could swerve and become unstable. Therefore always inspect the system immediately
if EBD control is suspended.
Fail-safe Function Malfunction Contents
Malfunction DTC
location number
warning
Power supply
B1317 Illuminated Illuminated Illuminated Illuminated
system
Power supply
B1318 Illuminated Illuminated Illuminated Illuminated
system
DSC/RSC
HU/CM B1342 Illuminated Illuminated Illuminated Illuminated
system
DSC/RSC
HU/CM B211B
illuminated
system
Pump motor,
motor relay C1095 Illuminated
systems
Pump motor,
motor relay C1096 Illuminated
systems
Valve relay
C1115 Illuminated
system
ON-BOARD DIAGNOSTIC
Warning light illumination status
Brake
system
warning
ABS DSC
light
indicator
(when
light light
parking
brake is
released)
Not Not
Illuminated Illuminated
illuminated
Not
Illuminated Illuminated
illuminated
Not
Illuminated Illuminated
illuminated
Not
Illuminated Illuminated
illuminated
Fail-safe function
Control status
TCS OFF ABS EBD
light control Control
Control Control
disabled disabled
Control Control
disabled disabled
Control Control
disabled disabled
Control Control
enabled enabled
Control Control
enabled enabled
Control Control
enabled enabled
Control Control
enabled enabled
id040200110300
TCS DSC RSC
control control control
Control Control Control
disabled disabled disabled
Control Control Control
disabled disabled disabled
Control Control Control
disabled disabled disabled
Control Control Control
enabled disabled disabled
Control Control Control
disabled disabled disabled
Control Control Control
disabled disabled disabled
Control Control Control
disabled disabled disabled
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