Mitsubishi Lancer Evolution X. Manual - part 158

DIAGNOSIS

TSB Revision

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-97

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

• MB991997: ASC check harness

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 C1046 set?

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

STEP 3. Scan tool diagnostic trouble code
Check whether DTC No. C100A, C1011, C1014, and C1041 
are simultaneously set.
Q: Are DTC C100A, C1011, C1014, and C1041 also set?

YES : Carry out the diagnosis for the diagnostic trouble 

codes that are set, and then go to Step 5.

NO :  Go to Step 4.

STEP 4. Scan tool service data
Check the following service data. (Refer to 

P.35C-276

.)

• Item No.01: FL wheel speed sensor

Q: Is the check result normal?

YES : Go to Step 16.
NO :  Go to Step 5.

DIAGNOSIS

TSB Revision

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-98

STEP 5. Voltage measurement at A-05 ASC-ECU connector
(1) Disconnect the ASC-ECU connector, connect the special 

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

(2) Turn the ignition switch to the ON position.
(3) Measure the voltage between the wheel speed sensor 

power supply terminal (signal terminal) No. 45 and the body 
ground as well as between the ground terminal No. 46 and 
the body ground.

OK: 1 volt or less

Q: Is the check result normal?

YES  : Go to Step 6.
NO (Not normal at the terminal No. 45 or 46) : Go to Step 

7.

STEP 6. Resistance measurement at A-05 ASC-ECU 
connector
(1) Disconnect the ASC-ECU connector, connect the special 

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

(2) Measure the resistance between the wheel speed sensor 

circuit power supply terminal (signal terminal) No. 45 and 
the body ground as well as between the ground terminal 
No. 46 and the body ground.

OK: No continuity

Q: Is the check result normal?

YES  : Go to Step 9.
NO (Not normal at the terminal No. 45 or 46) : Go to Step 

7.

AC400817CB

ASC-ECU

MB991997

Check harness

A-05 ASC-ECU
harness connector

AC400817CC

ASC-ECU

MB991997

Check harness

A-05 ASC-ECU
harness connector

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-99

STEP 7. Connector check: A-05 ASC-ECU connector, A-11 
wheel speed sensor <FL> connector
Q: Is the check result normal?

YES : Go to Step 8.
NO :  Repair the defective connector. Then go to Step 17.

STEP 8. Wiring harness check between A-05 ASC-ECU 
connector terminal No. 45 and A-11 wheel speed sensor 
<FL> connector terminal No. 1, and between A-05 
ASC-ECU connector terminal No. 46 and A-11 wheel speed 
sensor <FL> connector terminal No. 2

• Short circuit check of wheel speed sensor <FL> circuit

Q: Is the check result normal?

YES : Replace the wheel speed sensor <FL>. (Refer to 

P.35C-300

.) Then go to Step 17.

NO :  Repair the wiring harness. Then go to Step 17.

STEP 9. Voltage measurement at A-05 ASC-ECU connector
(1) Disconnect the ASC-ECU connector, connect the special 

tool ASC check harness (MB991997) to the ASC-ECU-side 
connector and the wiring harness-side connector, and then 
measure at the special tool connector side.

(2) Turn the ignition switch to the ON position.
(3) Measure the voltage between the wheel speed sensor 

circuit power supply terminal (signal terminal) No. 45 and 
the body ground.

OK: Battery positive voltage

Q: Is the check result normal?

YES : Go to Step 10.
NO :  Go to Step 12.

STEP 10. Wiring harness check between A-05 ASC-ECU 
connector terminal No. 45 and A-11 wheel speed sensor 
<FL> connector terminal No. 1, and between A-05 
ASC-ECU connector terminal No. 46 and A-11 wheel speed 
sensor <FL> connector terminal No. 2

• Open circuit check of wheel speed sensor <FL> circuit

Q: Is the check result normal?

YES : Go to Step 11.
NO :  Repair the wiring harness. Then go to Step 17.

AC400817CD

ASC-ECU

MB991997

Check harness

A-05 ASC-ECU
harness connector

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-100

STEP 11. Check of wheel speed sensor as a single unit
Refer to 

P.35C-303

.

Q: Is the check result normal?

YES : Go to Step 13.
NO :  Replace the wheel speed sensor <FL>. (Refer to 

P.35C-300

.) Then go to Step 17.

STEP 12. Connector check: A-05 ASC-ECU connector, A-11 
wheel speed sensor <FL> connector
Q: Is the check result normal?

YES : Go to Step 16.
NO :  Repair the defective connector. Then go to Step 17.

STEP 13. Check of wheel speed sensor installation status
Check the installation status of wheel speed sensor <FL> (dis-
connection of wheel speed sensor, looseness of mounting bolt, 
etc.).
Q: Is the check result normal?

YES : Go to Step 14.
NO :  Reinstall the wheel speed sensor <FL> correctly. 

(Refer to 

P.35C-300

.) Then go to Step 17.

STEP 14. Wheel bearing looseness check
NOTE: 

.

•

Wheel bearing looseness may increase the gap between 
the wheel speed sensor and the wheel speed detection 
magnet encoder.

•

Check the wheel bearing <FL> for looseness. (Refer to 
GROUP 26 

−

 On-vehicle Service 

P.26-7

.)

Q: Is the check result normal?

YES : Go to Step 15.
NO :  Replace the front hub assembly. (Refer to GROUP 26 

− Front Axle Hub Assembly 

P.26-9

.)

STEP 15. Check of wheel speed detection encoder
Check the encoder for adhesion of foreign materials or defor-
mation.
Q: Is the check result normal?

YES : Go to Step 16.
NO (Adhesion of foreign materials) : Clean the encoder 

so as not to disturb the magnetization pattern on the 
encoder while taking care of the magnet, magnetic 
substance, and magnetic attraction.

NO (Deformation) : Replace the front hub assembly. (Refer 

to GROUP 26 − Front Axle Hub Assembly 

P.26-9

.)

AC704652 AB

Oil seal

Magnetic 
encoder

Wheel 
bearing

Hub