ON-BOARD DIAGNOSTIC SYSTEM FUNCTION [DYNAMIC STABILITY CONTROL (DSC)]

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Malfunction detection function

• The malfunction detection function detects and displays malfunctions in the input/output signal system of the DSC HU/CM when the ignition switch is at the ON position.
• When the DSC HU/CM is activated, the following malfunction detection is performed.

  ― The ABS and brake system warning lights, DSC indicator lights and DSC OFF light 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. 10 km/h {6.2 mph} or more the pump motor is operated and malfunction diagnosis is performed again. Input/output signals are monitored for malfunction determination when the ignition is switched to ON.

• If the above malfunctions are detected, the corresponding lights are illuminated to alert the driver. DTCs can be output through the CAN_H and CAN_L of the DLC-2 using the external tester communication function. 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 LOCK position, even if the malfunctioning signal system has returned to normal.
• Since the DSC 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, EBD, TCS, DSC and brake assist control as shown in the fail-safe function malfunction contents table.

  Warning
  • If EBD control is prohibited the rear wheels could lock-up before the front wheels.If this occurs, the vehicle could yaw and become unstable. Therefore always inspect the system immediately if EBD control is prohibited.

Fail-safe Function Malfunction Contents

Malfunction location | DTC number | Fail-safe function
--- | --- | ---
Warning light illumination status | Control status
Mazda Modular Diagnostic System (M-MDS) display | ABS warning light | Brake system warning light (when parking brake is released) | DSC indicator light | DSC OFF light | ABS control | EBD control | TCS control | DSC control | Brake assist control
Brake control | Engine control
Power supply system | B1317 | Illuminated | Illuminated | Illuminated | Not illuminated | Control disabled | Control disabled | Control disabled | Control disabled | Control disabled | Control disabled
B1318 | Illuminated *1 | Not illuminated *2 | Illuminated *1 | Control disabled *3 | Control enabled *4 | Control disabled *3 | Control disabled *3 | Control disabled *3 | Control disabled *3
DSC HU/CM system | B1342 | Illuminated | Illuminated | Illuminated | Not illuminated | Control disabled | Control disabled | Control disabled | Control disabled | Control disabled | Control disabled
Brake switch system | B1484 | Illuminated *5 | Illuminated*19 | Illuminated | Not illuminated | Control disabled *6 | Control enabled *7 | Control disabled *6 | Control disabled *6 | Control disabled | Control disabled
C1954
DSC HU/CM configuration | B2477 | Illuminated *8 | Not illuminated | Illuminated *8 | Not illuminated | Control disabled | Control enabled *7 | Control disabled | Control disabled | Control disabled | Control disabled
Combined sensor system | B2741 | Not illuminated | Not illuminated | Illuminated | Not illuminated | Control enabled *7 | Control enabled | Control disabled *9 | Control disabled *9 | Control disabled | Control enabled *7
C2768
U2516
DSC OFF switch system | C1093 | Not illuminated | Not illuminated | Illuminated | Illuminated | Control enabled | Control enabled | Control disabled | Control disabled | Control disabled | Control enabled
Pump motor, motor relay systems | C1095 | Illuminated | Illuminated | Illuminated | Not illuminated | Control disabled | Control enabled *7 | Control disabled | Control disabled | Control disabled | Control disabled
C1096
LF ABS sensor rotor | C1141 | Illuminated | Not illuminated | Illuminated | Not illuminated | Control disabled *10 | Control enabled *7 | Control disabled | Control disabled | Control disabled | Control disabled
RF ABS sensor rotor | C1142
LR ABS sensor rotor | C1143
RR ABS sensor rotor | C1144
RF ABS wheel-speed sensor system | C1145 | Illuminated | Not illuminated | Illuminated | Not illuminated | Control disabled *10 | Control enabled *7 | Control disabled | Control disabled | Control disabled | Control disabled
LF ABS wheel-speed sensor system | C1155
RR ABS wheel-speed sensor system | C1165
LR ABS wheel-speed sensor system | C1175
RF ABS wheel-speed sensor/ABS sensor rotor systems | C1148 | Illuminated | Not illuminated | Illuminated | Not illuminated | Control disabled *10 | Control enabled *7 | Control disabled | Control disabled | Control disabled | Control disabled
LF ABS wheel-speed sensor/ABS sensor rotor systems | C1158
RR ABS wheel-speed sensor/ABS sensor rotor systems | C1168
LR ABS wheel-speed sensor/ABS sensor rotor systems | C1178
Valve relay system | C1186 | Illuminated | Illuminated | Illuminated | Not illuminated | Control disabled | Control disabled | Control disabled | Control disabled | Control disabled | Control disabled
C1266 | Not illuminated | Control enabled *7
LF outlet solenoid valve system | C1194 | Illuminated | Illuminated | Illuminated | Not illuminated | Control disabled | Control disabled | Control disabled | Control disabled | Control disabled | Control disabled
LF inlet solenoid valve system | C1198
RF outlet solenoid valve system | C1210
RF inlet solenoid valve system | C1214
LR outlet solenoid valve system | C1242
RR outlet solenoid valve system | C1246
LR inlet solenoid valve system | C1250
RR inlet solenoid valve system | C1254
RH traction control solenoid valve system | C1400 | Illuminated | Illuminated | Illuminated | Not illuminated | Control disabled | Control disabled | Control disabled | Control disabled | Control disabled | Control disabled
LH traction control solenoid valve system | C1410
RH stability control solenoid valve system | C1957
LH stability control solenoid valve system | C1958
ABS wheel-speed sensor (slip monitor) system | C1222 | Illuminated | Illuminated *11 | Illuminated | Not illuminated | Control disabled *12 | Control disabled *13 | Control disabled | Control disabled | Control disabled | Control disabled
LF ABS wheel-speed sensor system | C1233 | Illuminated | Not illuminated | Illuminated | Not illuminated | Control disabled *10 | Control enabled *7 | Control disabled | Control disabled | Control disabled | Control disabled
RF ABS wheel-speed sensor system | C1234
RR ABS wheel-speed sensor system | C1235
LR ABS wheel-speed sensor system | C1236
Combined sensor system | C1279 | Not illuminated | Not illuminated | Illuminated | Not illuminated | Control enabled *7 | Control enabled | Control disabled *9 | Control disabled *9 | Control disabled | Control enabled *7
C1280 | Illuminated *14 | Control disabled *9, 15 | Control disabled *9, 15 | Control disabled *15
C1281 | Illuminated | Control disabled *9 | Control disabled *9 | Control disabled
C1952 | Illuminated *16 | Control disabled *9, 17 | Control disabled *9, 17
C1959 | Illuminated | Control disabled *9 | Control disabled *9
Brake fluid pressure sensor system | C1290 | Illuminated *18 | Not illuminated | Illuminated | Not illuminated | Control disabled *10 | Control enabled *7 | Control disabled *9 | Control disabled *9 | Control disabled | Control disabled
C1953
Steering angle sensor system | C1295 | Not illuminated | Not illuminated | Illuminated | Not illuminated | Control enabled *7 | Control enabled | Control disabled *9 | Control disabled *9 | Control disabled | Control enabled *7
C1307
C1937
C1938 | Illuminated *14 | Control disabled *9, 15 | Control disabled *9, 15 | Control disabled *15
C1956 | Illuminated | Control disabled *9 | Control disabled *9 | Control disabled
Steering angle sensor (abnormal initialization) system | C1306 | Not illuminated | Not illuminated | Illuminated | Flash | Control enabled *7 | Control enabled | Control disabled *9 | Control disabled *9 | Control disabled | Control enabled *7
DSC control system | C1994 | Illuminated | Not illuminated | Illuminated | Not illuminated | Control disabled | Control enabled*7 | Control disabled | Control disabled | Control disabled | Control disabled
CAN communication system | U0073 | Not illuminated | Not illuminated | Illuminated | Not illuminated | Control enabled *7 | Control enabled | Control disabled | Control disabled | Control disabled | Control enabled *7
U0100
U0101
U0155
U1900
Abnormal message from PCM | U2023
CAN2 communication system | U0074 | Not illuminated | Not illuminated | Illuminated | Not illuminated | Control enabled *7 | Control enabled | Control disabled | Control disabled | Control disabled | Control enabled *7
U0123 | Control disabled *9 | Control disabled *9
U1901 | Control disabled | Control disabled

*1 :If the ignition voltage returns to normal, the light turns off.
*2 :If the ignition voltage is less than 7.6 V, the light illuminates. Afterwards, if the ignition voltage returns to normal, the light turns off.
*3 :If the ignition voltage returns to normal, control is enabled.
*4 :If the ignition voltage is less than 7.6 V, control is disabled. Afterwards, if the ignition voltage returns to normal, control is enabled.
*5 :If an error is detected during the ABS/TCS control, the light illuminates after finishing the control.
*6 :If an error is detected during the ABS/TCS control, the control is disabled after finishing the control.
*7 :Control which requires sensor data is inhibited.
*8 :If the configuration data is not within the specification, the light flashes.
*9 :If an error is detected during the TCS control, the control is disabled after finishing the control.
*10 :If an error is detected during the ABS control, the control is disabled after finishing the control.
*11 :If an abnormal cornering direction is detected, the light does not illuminate.
*12 :If an abnormal cornering direction is detected during the ABS control, the control is disabled after finishing the control.
*13 :If an abnormal cornering direction is detected, the control is not disabled.
*14 :When an abnormal cornering direction is detected, the light turns off if the normal condition is verified the next time the system is activated.
*15 :When an abnormal cornering direction is detected, control is enabled if the normal condition is verified the next time the system is activated.
*16 :If the system returns to normal, the light turns off. However, if another error is detected within 180 s, the light remains illuminated until the ignition switch is turned LOCK position.
*17 :If the system returns to normal, control is enabled. However, if another error is detected within 180 s, control is disabled until the ignition switch is turned LOCK position.
*18 :If an error is detected during the ABS control, the light illuminates after finishing the control.
*19 :Vehicles without malfunction warning light. (Applied VIN (assumed): NC18**215550—, NC18**250831—, NC30**202488—, NCA8**251024—)