Mitsubishi Evolution X. Manual — part 784

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-143

STEP 9. Connector check: C-43 joint connector, C-47
intermediate connector, C-48 stoplight switch connector,
C-304 ETACS-ECU connector, C-309 ETACS-ECU
connector, C-312 ETACS-ECU connector, D-11
intermediate connector, D-17 intermediate connector, F-05
high-mounted stoplight, F-06 rear combination light
(stoplight: RH), F-25 rear combination light (stoplight: LH),
F-27 intermediate connector
Q: Is the check result normal?

YES : Go to Step 10.
NO : Repair the defective connector. Then, replace fuse

No. 2.

STEP 10. Wiring harness check between C-48 stoplight
switch connector and C-312 ETACS-ECU connector and
C-43 joint connector
(1) Disconnect C-43 joint connector, C-48 stoplight switch

connector, and C-312 ETACS-ECU connector.

(2) Check the continuity (short to ground) between C-48

stoplight switch connector terminal No. 1 and the ground.

OK: No continuity

Q: Is the check result normal?

YES : Go to Step 11.
NO : The short circuit may be present in the wiring harness

between C-48 stoplight switch connector terminal No.
1 and C-43 joint connector terminal No. 2 or between
C-48 stoplight switch connector terminal No. 1 and
C-312 ETACS-ECU connector terminal No. 16.
Repair the damaged wiring harness. Then, replace
fuse No. 2.

STEP 11. Harness check between C-48 stoplight switch
connector and C-304 ETACS-ECU connector
(1) Disconnect C-48 stoplight switch connector and C-304

ETACS-ECU connector.

(2) Check the continuity (short to ground) between C-48

stoplight switch connector terminal No. 2 and the ground.

OK: No continuity

Q: Is the check result normal?

YES : Go to Step 12.
NO : The short circuit may be present in the wiring harness

between C-48 stoplight switch connector terminal No.
2 and C-304 ETACS-ECU connector terminal No. 1.
Then, replace fuse No. 2.

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-144

STEP 12. Wiring harness check between C-43 joint
connector and F-06 rear combination light (stoplight: RH)
connector.
(1) Disconnect C-43 joint connector and F-06 rear combination

light (stoplight: RH) connector.

(2) Check the continuity (short to ground) between C-43 joint

connector terminal No. 1 and the ground.

OK: No continuity

Q: Is the check result normal?

YES : Go to Step 13.
NO : The short circuit may be present in the wiring harness

between C-43 joint connector terminal No.1 and F-06
rear combination light (stoplight: RH) connector
terminal No.4. Then, replace fuse No. 2.

STEP 13. Check the wiring harness between C-43 joint
connector and F-25 rear combination light (stoplight: LH)
connector, and between C-43 joint connector and F-05
high mounted stoplight connector.
(1) Disconnect C-43 joint connector, F-05 high-mounted

stoplight connector and F-25 rear combination light
(stoplight: LH) connector.

(2) Check the continuity (short to ground) between C-43 joint

connector terminal No. 12 and the ground.

OK: No continuity

Q: Is the check result normal?

YES : Replace fuse No. 2.
NO : The short circuit may be present in the wiring harness

between C-43 joint connector terminal No. 12 and
F-05 high-mounted stoplight connector terminal No.1
or between C-43 joint connector terminal No.12 and
F-05 rear combination light (stoplight: LH) connector
terminal No.4. Repair the damaged wiring harness.
Then, replace fuse No. 2.

STEP 14. Voltage measurement at C-304 ETACS-ECU
connector

CAUTION

The measurement must be performed without the brake
pedal depressed (not operated).
Measure the voltage between the terminal No. 1 and the body
ground by backprobing.

OK: System voltage

Q: Is the check result normal?

YES : Go to Step 15.
NO : Replace the ETACS-ECU. (Refer to GROUP 54A

−

ETACS-ECU

P.54A-676

.) Then, go to Step 19.

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-145

STEP 15. Voltage measurement at C-48 stoplight switch
connector
(1) Disconnect the connector, and measure at the wiring

harness side.

(2) Measure the voltage between the terminal No. 2 and the

body ground.

OK: System voltage

Q: Is the check result normal?

YES : Go to Step 16.
NO : An open circuit may be present in the wiring harness

between C-304 ETACS-ECU connector terminal No.
1 and C-48 stoplight switch connector terminal No. 2.
Repair the wiring harness.

STEP 16. Voltage measurement at C-43 joint connector

CAUTION

The measurement must be performed with the brake pedal
depressed.
(1) Disconnect the connector, and measure at the wiring

harness side.

(2) Measure the voltage between the terminal No. 2 and the

body ground.

OK: System voltage

Q: Is the check result normal?

YES : Go to Step 17.
NO : An open circuit may be present in the wiring harness

between C-43 joint connector terminal No. 2 and C-48
stoplight switch connector terminal No. 1. Repair the
wiring harness.

STEP 17. Voltage measurement at C-312 ETACS-ECU
connector
(1) Without disconnecting the connector, measure by

backprobing.

(2) Measure the voltage between the terminal No. 16 and the

body ground.

OK:

The brake pedal is released: Approximately 0 V
The brake pedal is depressed: System voltage

Q: Is the check result normal?

YES : Go to Step 18.
NO : An open circuit may be present in the wiring harness

between C-312 ETACS-ECU connector terminal No.
16 and C-48 stoplight switch connector terminal No.
1. Repair the wiring harness.

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-146

STEP 18. Check whether the DTC is reset.
Q: Is DTC 1000 set?

YES : Replace the hydraulic unit (incorporates in

ASC-ECU).(Refer to

P.35C-272

.) Then go to Step 19.

NO : Intermittent malfunction. (Refer to GROUP 00

− How

to Cope with Intermittent Malfunction

P.00-15

.)

STEP 19. Check whether the DTC is reset.
Q: Is DTC 1000 set?

YES : Return to Step 1.
NO : The procedure is complete.

DTC C123B: Prolonged operation of ASC

CAUTION

• If there is any problem in the CAN bus lines, an incor-

rect diagnostic trouble code may be set. Prior to this
diagnosis, diagnose the CAN bus lines.

• Whenever the ECU is replaced, ensure that the CAN

bus lines are normal.

• When the steering wheel sensor is replaced or

re-installed, always perform the calibration to make
ASC-ECU learn the neutral point. (Refer to

P.35C-267

.)

• Do not drop the G and yaw rate sensor or subject it to a

shock.

• When the G and yaw rate sensor is replaced, always

perform the calibration to make ASC-ECU learn the
neutral point. (Refer to

P.35C-266

.)

• When the hydraulic unit (integrated with ASC-ECU) is

replaced, always perform the calibration of steering
wheel sensor, G and yaw rate sensor, brake fluid pres-
sure sensor, cut valve, and inlet valve.(Refer to

P.35C-266

,

P.35C-267

,

P.35C-268

, and

P.35C-269

.)

.

CIRCUIT OPERATION

ASC-ECU controls ASC by calculating the data sent from the
wheel speed sensor, steering wheel sensor, and G and yaw
rate sensor.

.

DTC SET CONDITIONS

This diagnostic trouble code is set when ASC control is oper-
ated for a prolonged period.
NOTE: This diagnostic trouble code may be set when the vehi-
cle runs on a slippery or rough road, or when the vehicle per-
forms a steady state cornering.

.