Mitsubishi Outlander GS45X. Manual — part 417

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-95

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 (Refer to
GROUP 54C

− CAN Bus Line Diagnostic Flow

P.54C-10

).

• Whenever ECU is replaced, ensure that the CAN bus

lines are normal.

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

replaced, always carry out the calibration of the steer-
ing wheel sensor, the G and yaw rate sensor and brake
fluid pressure sensor (Refer to

P.42C-10

,

P.35C-282

and

P.35C-284

).

.

OPERATION

• The wheel speed sensor is a kind of a pulse generator. It

consists of encoders (a plate on which north and south pole
sides of the magnets are arranged alternately) for detecting
the wheel speed which rotates at the same speed of the
wheels and wheel speed sensors. This sensor outputs fre-
quency pulse signals in proportion to the wheel speed.

• The pulse signals, which the wheel speed sensor creates,

are sent to ASC-ECU. ASC-ECU uses the frequency of the
pulse signals to determine the wheel speed.

.

DTC SET CONDITIONS

This diagnostic trouble code is set if any malfunction below is
found:

• When the brake fluid pressure is decreased for a long time.

• When the brake fluid pressure is held for a long time.

.

PROBABLE CAUSES

• Damaged wiring harness and connectors

• External noise interference

• Malfunction of wheel speed sensor

• ASC-ECU malfunction

• Excessive gap between the wheel speed sensor and the

magnetic encoder for wheel speed detection

• Adhesion of foreign materials on the wheel speed sensor

• Adhesion of foreign materials on the magnetic encoder for

wheel speed detection

• Wheel bearing malfunction

• Improper installation of the wheel speed sensor

• Deformation of the magnetic encoder for wheel speed

detection

• Disturbance of magnetization pattern for magnetic encoder

for wheel speed detection

• Missing teeth of the magnetic encoder for wheel speed

detection

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-96

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.
Use scan tool to 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

−

CAN Bus Diagnostics Table

P.54C-17

). On

completion, go to Step 2.

STEP 2. DTC recheck after resetting CAN bus lines
Q: Is DTC C1046 set?

YES : Go to Step 3.
NO : The procedure is complete.

STEP 3. Using scan tool MB991958, check the DTC
Check that the DTC C100A, C1011, C1014, or C1041 is also
set.
Q: Is the DTC C100A, C1011, C1014, or C1041 also set?

YES : Carry out the diagnosis for the relevant DTC.
NO : Go to Step 4.

STEP 4. Using scan tool MB991958, check the data list
Check the following data list (Refer to

P.35C-270

).

• Item No.01: FL wheel speed sensor

Q: Is the check result normal?

YES : Go to Step 11.
NO : Go to Step 5.

STEP 5. Connector check: A-02 ASC-ECU connector, A-11
front wheel speed sensor <LH> connector
Q: Is the check result normal?

YES : Go to Step 6.
NO : Repair the defective connector. Then go to Step 13.

STEP 6. Wiring harness check between A-02 ASC-ECU
connector terminal No.45 and A-11 front wheel speed
sensor <LH> connector terminal No.1 and between A-02
ASC-ECU connector terminal No.46 and A-11 front wheel
speed sensor <LH> connector terminal No.2.
Q: Is the check result normal?

YES : Go to Step 7.
NO : Repair the wiring harness. Then go to Step 13.

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-97

STEP 7. Check for wheel speed sensor <FL> installation
Check how the wheel speed sensor <FL> is installed (Discon-
nection of wheel speed sensor <FL>, loose mounting bolt,
etc.).
Q: Is the check result normal?

YES : Go to Step 8.
NO : Reinstall the wheel speed sensor <FL> correctly

(Refer to

P.35C-288

). Then go to Step 8.

STEP 8. Check for wheel speed sensor <FL> output
current
Refer to

P.35C-277

.

Q: Is the check result normal?

YES : Go to Step 9.
NO : Replace the wheel speed sensor <FL> (Refer to

P.35C-288

). Then go to Step 12.

STEP 9. Check for wheel bearing looseness
NOTE:

.

•

Loose wheel bearing may increase the gap between the
wheel speed sensor <FL> and the wheel speed detection
magnet encoder.

•

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

−

Wheel Bearing Play Check

P.26-11

).

Q: Is the check result normal?

YES : Go to Step 10.
NO : Replace the wheel bearing <FL> (Refer to GROUP 26

− Front axle hub assembly

P.26-18

). Then go to Step

13.

STEP 10. 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 11.
NO (Adhesion of foreign materials) : Remove the foreign

materials and clean the encoder so as not to disturb
the magnetization pattern on it while taking care of the
magnet, magnetic substance, and magnetic
attraction. Then go to Step 13.

NO (Deformation) : Replace the wheel bearing <FL>

(Refer to GROUP 26

− Front axle hub assembly

P.26-18

). Then go to Step 13.

AC504925

Oil seal

Magnetic
encoder

AC

Wheel
bearing

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-98

STEP 11. Check whether the DTC is reset.
(1) Erase the DTC.
(2) Drive the vehicle at 12mph (20 km/h) or higher.

NOTE: The ABS warning light does not turn OFF in some
cases unless the vehicle runs at 12mph (20 km/h) or higher.

Q: Is DTC C1046 set?

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

P.35C-288

). Then go to Step 12.

NO : Intermittent malfunction (Refer to GROUP 00

− How

to Use Troubleshooting/How to Cope with Intermittent
Malfunctions

P.00-15

).

STEP 12. Check whether the DTC is reset.
(1) Erase the DTC.
(2) Drive the vehicle at 12 mph (20 km/h) or higher.

NOTE: The ABS warning light does not turn OFF in some
cases unless the vehicle runs at 12 mph (20 km/h) or
higher.

Q: Is DTC C1046 set?

YES : Replace the hydraulic unit (integrated with ASC-ECU)

(Refer to

P.35C-287

). Then go to Step 13.

NO : The procedure is complete.

STEP 13. Check whether the DTC is reset.
(1) Erase the DTC.
(2) Drive the vehicle at 12 mph (20 km/h) or higher.

NOTE: The ABS warning light does not turn OFF in some
cases unless the vehicle runs at 12 mph (20 km/h) or
higher.

Q: Is DTC C1046 set?

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