Mitsubishi Lancer Evolution X. Manual — part 185

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-205

STEP 14. Resistance measurement at A-05 ASC-ECU
connector
(1) Disconnect the connector, connect the special tool ASC

check harness (MB991997) to the wiring harness-side
connector, and measure the voltage at the special tool
connector side.
NOTE: Do not connect the special tool to ASC-ECU.

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

body ground, and between the terminal No.47 and the body
ground

OK: Continuity exists (2 Ω or less)

Q: Is the check result normal?

YES : Go to Step 15.
NO : An open circuit may be present in the ground circuit.

Repair the wiring harness between A-05 ASC-ECU
connector terminal No. 16 and the body ground as
well as between A-05 ASC-ECU connector terminal
No. 47 and the body ground, and then go to Step 15.

STEP 15. Check whether the DTC is reset.
(1) Erase the diagnostic trouble code.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Turn the ignition switch to the "ON" position.
(4) Perform a test run of the vehicle at the vehicle speed of 12

mph (20 km/h) or more. Then, check if the diagnostic
trouble code is set in ASC-ECU.

Q: Is the DTC set?

YES (DTC C1608 is set) : Replace the hydraulic unit

(integrated with ASC-ECU). (Refer to

P.35C-298

YES (DTC other than C1608 is set) : Carry out the

applicable troubleshooting for the DTC.

NO : This diagnosis is complete.

AC400817CO

ASC-ECU

MB991997

A-05 ASC-ECU
harness connector

Check harness

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-206

DTC C2002: Abnormality in valve calibration

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.

• During the calibrations of cut valve and inlet valve, do

not depress the brake pedal or subject the vehicle to a
vibration.

• 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

CIRCUIT OPERATION

ASC-ECU stores the correction values of cut valve and inlet
valve in the EEPROM.

DTC SET CONDITIONS

This diagnostic trouble code is set when the calibration of the
cut valve or inlet valve has not been performed, or when the
correction value of cut valve or inlet valve is abnormal.

PROBABLE CAUSES

• ASC-ECU malfunction
• Noise interference

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
lines.
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-15

.) After repairing the CAN

bus line, go to Step 2.

STEP 2. DTC recheck after repairing the CAN bus line
Q: Is DTC C2002 set?

YES : Go to Step 3.
NO : This diagnosis is complete.

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-207

STEP 3. Check for diagnostic trouble codes
Check if any diagnostic trouble code other than No. C2002 is
set in ASC-ECU.
Q: Is the check result normal?

YES : Carry out the diagnosis for the diagnostic trouble

code that is set.(Refer to

P.35C-22

.) Then go to Step

NO : Go to Step 4.

STEP 4. Cut valve and inlet valve calibration
Refer to

P.35C-295

Q: Is the calibration performed normally?

YES : Go to Step 7.
NO : Go to Step 5.

STEP 5. Service data check
Check the following service data. (Refer to

P.35C-276

• Item No. 14: Brake switch

Q: Is the check result normal?

YES : Go to Step 6.
NO : Check the stoplight switch. (Refer to GROUP 35A −

Stoplight Switch Check

P.35A-25

STEP 6. Cut valve and inlet valve calibration
Refer to

P.35C-295

Q: Is the calibration performed normally?

YES : Go to Step 7.
NO : Replace the hydraulic unit (integrated with

ASC-ECU).(Refer to

P.35C-298

.) Then, return to Step

STEP 7. Check whether the DTC is reset.
Q: Is DTC C2002 set?

YES : Return to Step 1.
NO : This diagnosis is complete.

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-208

DTC U0001: Bus-off

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.

• If diagnostic trouble code U0001 is set in ASC-ECU,

always diagnose CAN bus lines. If there is any fault in
the CAN bus lines, an incorrect DTC may be set.

• Whenever the ECU is replaced, ensure that the CAN

bus lines are normal.

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

replaced, after turning the ignition switch ON and OFF
(vehicle information from ETACS-ECU is registered),
always perform the calibration of steering wheel sen-
sor, G and yaw rate sensor, brake fluid pressure sen-
sor, cut valve, and inlet valve.(Refer to

, and

DTC SET CONDITIONS

This diagnostic trouble code is set when ASC-ECU has ceased
CAN communication (bus off).

PROBABLE CAUSES

• Wiring harness or connector failure of CAN bus line
• ASC-ECU malfunction
• ECU malfunction of other system

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
lines.
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-15

.) After repairing the CAN

bus line, go to Step 3.

STEP 2. Check whether the DTC is reset.
Q: Is DTC U0001 set?

YES : Replace the hydraulic unit (incorporates in

ASC-ECU).(Refer to

P.35C-298

.) Then go to Step 3.

NO : Intermittent malfunction. (Refer to GROUP 00 − How

to Cope with Intermittent Malfunction