Mitsubishi Outlander GS45X. Manual — part 400

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-27

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.35C-283

,

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

ASC-ECU monitors the voltage fluctuation in each wheel speed
sensor circuit. If ASC-ECU detects the open or short circuit in
the circuit, it will set a diagnostic trouble code.

.

PROBABLE CAUSES

Current trouble

• Damaged wiring harness and connectors

• Noise interference

• Malfunction of wheel speed sensor

• ASC-ECU malfunction

AC901112

Connectors: A-02, A-59

A-02 (B)

AO

A-59 (B)

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-28

Past trouble

• Carry out diagnosis with particular emphasis on wiring har-

ness and connector failures between ASC-ECU and the
wheel speed sensor. For diagnosis procedures, refer to
How to treat past trouble (GROUP 00

− How to Use Trou-

bleshooting/How to Treat Past Trouble

P.00-17

).

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-10

). On

completion, go to Step 2.

STEP 2. DTC recheck after resetting CAN bus lines
Q: Is DTC C1015 set?

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

STEP 3. Using scan tool MB991958, check data list
Check the following data list (Refer to

P.35C-270

).

• Item No.02: FR wheel speed sensor

Q: Is the check result normal?

YES : Intermittent malfunction (Refer to GROUP 00

− How

to Use Troubleshooting/How to Cope with Intermittent
Malfunctions

P.00-15

).

NO : Go to Step 4.

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-29

STEP 4. Voltage measurement at the A-02 ASC-ECU
connector
(1) Disconnect the ASC-ECU connector, connect special tool

ASC check harness (MB991997) to the harness-side
connector, and then measure the voltage 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.34 and the body
ground and between the wheel speed sensor ground
terminal No.33 and the body ground.

OK: 1 Volt or less

Q: Is the check result normal?

YES : Go to Step 5.
NO (Not normal at the terminal No.34 or 33) : Go to Step

6.

STEP 5. Resistance measurement at A-02 ASC-ECU
connector
(1) Disconnect the ASC-ECU connector, connect special tool

ASC check harness (MB991997) to the harness-side
connector, and then measure the resistance 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

power supply terminal (signal terminal) No.34 and the body
ground and between the wheel speed sensor ground
terminal No.33 and the body ground.

OK: No continuity

Q: Is the check result normal?

YES : Go to Step 8.
NO (Not normal at the terminal No.34 or 33) : Go to Step

6.

AC611137BE

ASC-ECU

MB991997

A-02 ASC-ECU
harness connector

Check harness

AC611137

ASC-ECU

MB991997

A-02 ASC-ECU
harness connector

BF

Check harness

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-30

STEP 6. Connector check: A-02 ASC-ECU connector, A-59
front wheel speed sensor <RH> connector
Q: Is the check result normal?

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

STEP 7. Wiring harness check between A-02 ASC-ECU
connector terminal No.34 and A-59 front wheel speed
sensor <RH> connector terminal No.1 and between A-02
ASC-ECU connector terminal No.33 and A-59 front wheel
speed sensor <RH> connector terminal No.2.

• Check for short circuit in front wheel speed sensor <RH>

circuit

Q: Is the check result normal?

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

P.35C-288

).

NO : Repair the wiring harness.

STEP 8. Voltage measurement at the A-02 ASC-ECU
connector
(1) Disconnect the ASC-ECU connector, connect special tool

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

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

power supply terminal (signal terminal) No.34 and body
ground, and between the ground terminal No.33 and body
ground.

OK:

Terminal No.34 and body ground: Approximately

system voltage

Terminal No.33 and body ground: 1 volt or less

Q: Is the check result normal?

YES : Go to Step 9.
NO : Go to Step 11.

AC611138AL

ASC-ECU

MB991997

A-02 ASC-ECU
harness connector

Check harness