Mitsubishi Lancer Evolution X. Manual - part 191

DIAGNOSIS

TSB Revision

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-229

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 3.
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 U1417 set?

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

STEP 3. Check for diagnostic trouble codes
Check if diagnostic trouble code No. C121C is set in ASC-ECU.
Q: Is the check result normal?

YES : Perform troubleshooting for the diagnostic trouble

code that is set. (Refer to

P.35C-166

NO : Go to Step 4.

STEP 4. Scan tool diagnostic trouble code for other
systems
Use scan tool to check whether any diagnostic trouble code
related to vehicles information is set or not by the ETACS-ECU
or engine control module (ECM).
Q: Is any DTC set?

YES : Perform troubleshooting for the diagnostic trouble

code that is set.

NO : Go to Step 5.

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-230

STEP 5. ETACS-ECU coding data check
Using the scan tool, check if there is any abnormality to the fol-
lowing coding data stored in the ETACS-ECU. (Refer to
GROUP 00 − Coding Table

P.00-26

Vehicle line

OK: LANCER EVO

Transaxle

OK (Vehicles without TC-SST): 5MT
OK (Vehicles with TC-SST): TC-SST

Engine type

OK: D4 V.V.T. 2.0L TC

Engine power

OK: Normal

Chassis Type for A.S.C.

OK: Type 1

Final drive

OK: AWD FF Base

Transfer

OK: ACD

SAS

OK: Present

AWD

OK: Not present

TCM

OK (Vehicles without TC-SST): Not present
OK (Vehicles with TC-SST): Present

ACDAYC

OK: Present

Q: Is the check result normal?

YES : Go to Step 6.
NO : Replace the ETACS-ECU. (Refer to GROUP 54A −

ETACS-ECU

P.54A-742

.) Then go to Step 10.

STEP 6. Engine control module coding data check
Using the scan tool, check if there is any abnormality to the
coding data stored in the engine control module. (Refer to
GROUP 00 − Coding Table

P.00-26

Q: Is the check result normal?

YES : Go to Step 7.
NO : Replace the engine control module. (Refer to GROUP

13A − Engine Control Module

P.13A-888

.) Then go to

Step 10.

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-231

STEP 7. Check of ETACS-ECU part number
Check the part number of ETACS-ECU.
Q: Is the check result normal?

YES : Go to Step 8.
NO : Replace the ETACS-ECU. (Refer to GROUP 54A −

ETACS-ECU

P.54A-742

.) Then go to Step 10.

STEP 8. Check of ASC-ECU part number
Check the part number of ASC-ECU.
Q: Is the check result normal?

YES : Go to Step 9.
NO : Replace the hydraulic unit (incorporates in

ASC-ECU).(Refer to

P.35C-298

.) Then go to Step 10.

STEP 9. Check whether the DTC is reset.
Q: Is DTC U1417 set?

YES : Replace the hydraulic unit (incorporates in

ASC-ECU).(Refer to

P.35C-298

.) Then go to Step 10.

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

to Cope with Intermittent Malfunction

P.00-15

STEP 10. Check whether the DTC is reset.
Q: Is DTC U1417 set?

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

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-232

Trouble symptom chart

M1355006900587

CAUTION

• ABS may operate in the following conditions without hard braking: Low mu road surface,

high-speed turn, and bumpy road surface. When asking the customers, confirm if they have
encountered ABS operation in corresponding conditions.

• Even when the ASC operation display does not appear, the ASC operation noise (pump, motor,

and others) may be generated. This occurs because the pump, motor, and others operate to accu-
mulate the braking force before the application of braking force to wheels, and it is not a malfunc-
tion.

• During ABS operation, as the brake pedal is gradually drawn inward, the noise is generated. This

occurs because the brake line pressure varies intermittently to prevent the wheel lock, and it is
not a malfunction.

CAUTION

During diagnosis, a DTC associated with other system may be set when the ignition switch is turned
ON with connector(s) disconnected. On completion, confirm all systems for diagnostic trouble
code(s). If diagnostic trouble code(s) are set, erase them all.

Trouble symptoms

Inspection
procedure
number

Reference
page

The scan tool cannot communicate
with the ABS/ASC system.

The scan tool cannot communicate
with all systems.

−

Refer to
GROUP 54C
−

Troubleshooti
ng

P.54C-15

The scan tool cannot communicate
only with ASC-ECU.

P.35C-233

With the parking brake released, the brake warning light remains illuminated
(ABS warning light is turned off).