Mitsubishi Evolution X. Manual — part 804

DIAGNOSIS

TSB Revision

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-223

STEP 6. Connector check: C-312 ETACS-ECU connector,
A-09 brake fluid level switch connector
Q: Is the check result normal?

YES : Go to Step 7.
NO : Repair the defective connector.

STEP 7. Voltage measurement at A-09 brake fluid level
switch connector
(1) Disconnect the connector, and measure at the wiring

harness side.

(2) Turn the ignition switch to the ON position.
(3) 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 9.
NO : Go to Step 8.

STEP 8. Voltage measurement at C-312 ETACS-ECU
connector

CAUTION

Keep the C-312 ETACS-ECU connector remain connected,
then disconnect A-09 brake fluid level switch connector.
(1) Turn the ignition switch to the ON position.
(2) Measure the voltage between the terminal No. 1 and the

body ground by backprobing.

OK: Approximately battery voltage

Q: Is the check result normal?

YES : Repair the wiring harness between C-312

ETACS-ECU connector terminal No. 1 and A-09
brake fluid level switch connector terminal No. 1.

NO : Replace the ETACS-ECU. (Refer to GROUP 54A

−

ETACS

P.54A-676

.) Then go to Step 18.

STEP 9. Wiring harness check: Between A-09 brake fluid
level switch connector and the body ground
Check for an open circuit in the wiring harness between A-09
brake fluid level switch connector terminal No. 1 and the body
ground.
Q: Is the check result normal?

YES : Go to Step 10.
NO : Repair the wiring harness.

STEP 10. Parking brake lever stroke check
Refer to GROUP 36

− On-vehicle Service

P.36-11

Q: Is the check result normal?

YES : Go to Step 11.
NO : Adjust the parking brake lever stroke (Refer to

GROUP 36

− On-vehicle Service

P.36-11

.) Then, go

to Step 18.

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-224

STEP 11. Parking brake switch check
Refer to GROUP 36

− On-vehicle Service

P.36-12

Q: Is the check result normal?

YES : Go to Step 12.
NO : Replace the parking brake switch (Refer to GROUP

− Parking Brake Lever

P.36-13

.) Then, go to Step

18.

STEP 12. Connector check: C-122 parking brake switch
connector
Q: Is the check result normal?

YES : Go to Step 13.
NO : Repair the defective connector.

STEP 13. Voltage measurement at C-122 parking brake
switch connector
(1) Disconnect the connector, and measure at the wiring

harness side.

(2) Turn the ignition switch to the ON position.
(3) Measure the voltage between the terminal No. 1 and the

body ground.

OK: System voltage

Q: Is the check result normal?

YES : Go to Step 17.
NO : Go to Step 14.

STEP 14. Connector check: C-04 combination meter
connector, C-23 intermediate connector
Q: Is the check result normal?

YES : Go to Step 15.
NO : Repair the defective connector.

STEP 15. Voltage measurement at C-04 combination meter
connector
(1) Release the parking brake lever (not operated).
(2) Turn the ignition switch to the ON position.
(3) Without disconnecting the connector, measure the voltage

between the terminal No. 4 and the body ground by
backprobing.

OK: System voltage

Q: Is the check result normal?

YES : Go to Step 17.
NO : Go to Step 16.

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-225

STEP 16. Wiring harness check: Between C-04
combination meter connector and C-122 parking brake
switch connector
Check for a short circuit in the wiring harness between C-04
combination meter connector terminal No. 4 and C-122 parking
brake switch connector terminal No. 1.
Q: Is the check result normal?

YES : Go to Step 17.
NO : Repair the wiring harness.

STEP 17. Retest the system.
Q: Does the brake warning light turn ON and OFF normally

according to the parking brake lever operation?
YES : Intermittent malfunction. (Refer to GROUP 00

− How

to Cope with Intermittent Malfunction

P.00-15

NO : Replace the combination meter assembly. (Refer to

GROUP 54A

− Combination Meter

P.54A-101

.) Then,

go to Step 18.

STEP 18. Retest the system.
Q: Does the brake warning light turn ON and OFF normally

according to the parking brake lever operation?
YES : The procedure is complete.
NO : Return to Step 1.

Inspection Procedure 3: The ABS warning light does not illuminate when ignition switch is turned to
the ON position (engine stopped).

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 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

SYSTEM OPERATION

• ASC-ECU sends the illumination signal of ABS warning

light to the combination meter through ETACS-ECU via
CAN communication.

• When the ignition switch is turned ON, ASC-ECU illumi-

nates the ABS warning light via ETACS-ECU for approxi-
mately 3 seconds for the purpose of bulb check.

DIAGNOSIS

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ACTIVE SKID CONTROL SYSTEM (ASC)

35C-226

TECHNICAL DESCRIPTION (COMMENT)

In the case of this trouble symptom, there may be a malfunction
to the CAN bus line, ETACS-ECU, combination meter, or
ASC-ECU.

PROBABLE CAUSES

• Damaged harness wires and connectors

• Malfunction of the ETACS-ECU

• Malfunction of the combination meter

• Malfunction of ASC-ECU

• Abnormality with ETACS-ECU coding data

DIAGNOSIS

Required Special Tools:

• MB991958 Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827 M.U.T.-III USB Cable

• MB991910 M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, diagnose the CAN bus
line.
Using scan tool MB991958, diagnose the CAN bus lines.
Q: Is the check result normal?

YES : Go to Step 2.
NO : Repair the CAN bus lines. (Refer to GROUP 54C

−

Troubleshooting

P.54C-14

.) Then go to Step 8.

STEP 2. Scan tool diagnostic trouble code
Using scan tool, check the diagnostic trouble code for ASC sys-
tem.
Q: Is the DTC set?

YES : Carry out the diagnosis for the diagnostic trouble

code. (Refer to

P.35C-20

NO : Go to Step 3.

STEP 3. M.U.T.-III actuator test
Perform the following actuator tests from the combination
meter system to check if the ABS warning light is illuminated.
(Refer to GROUP 54A

− Combination Meter, Actuator Test

Table

P.54A-82

• Item 07: Indicator1

Q: Is the check result normal?

YES : Go to Step 4.
NO : Carry out the diagnosis of the combination meter.

(Refer to GROUP 54A

− Combination Meter, Trouble

Symptom Chart

P.54A-59

.) Then go to Step 8.

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