Mitsubishi Outlander XL. Manual — part 653

CIRCUIT 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
frequency 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

Past trouble

｠

Carry out diagnosis with particular emphasis on wiring
harness 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 Cope with
Intermittent Malfunction P.00-15).

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. M.U.T.-III CAN bus diagnostics
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 54D - CAN

Bus Diagnostics table P.54D-17.) On completion, go to
Step 2.

STEP 2. Diagnostic trouble code recheck after resetting
CAN bus lines

Q:Is the diagnostic trouble code No. C1015 set?

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-19

DIAGNOSIS

YES:

Go to Step 3.

NO:

The procedure is complete.

STEP 3. M.U.T.-III data list
Check the following service data.

｠

Item No.02: FR wheel speed sensor

Q:Is the check result normal?

YES:

Intermittent malfunction (Refer to GROUP 00 - How

to Cope with Intermittent Malfunction P.00-15).

NO:

Go to Step 4.

STEP 4. Voltage measurement at the A-02 ASC-ECU
connector

ZC601293 0014

ASC-ECU

MB991997

Check harness

A-02 ASC-ECU
harness connector

(1)

Disconnect the ASC-ECU connector, connect special tool
MB991997 to the harness-side connector, and then measure
the resistance at the special tool connector side.

NOTE:

Do not connect the special tool MB991997 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/the ground terminal
No. 33 and the body ground.

OK: 0 volt

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.

35C-20

ACTIVE SKID CONTROL SYSTEM (ASC)

DIAGNOSIS

STEP 5. Resistance measurement at A-02 ASC-ECU
connector

ZC601293 0000

ASC-ECU

MB991997

Check harness

A-02 ASC-ECU
harness connector

(1)

Disconnect the ASC-ECU connector, connect special tool
MB991997 to the harness-side connector, and then measure
the resistance at the special tool connector side.

NOTE:

Do not connect the special tool MB991997 to ASC-

ECU.

(2)

Resistance between the wheel speed sensor power supply
terminal (signal terminal) No. 34/the 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.

STEP 6. Connector check: A-02 ASC-ECU connector, A-59
wheel speed sensor <FR> 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. 34/33 and A-59 wheel speed sensor
<FR> connector terminal No. 1/2

｠

Check for short circuit in wheel speed sensor <FR> circuit

Q:Is the check result normal?

YES:

Replace the wheel speed sensor <FR>.

NO:

Repair the wiring harness.

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-21

DIAGNOSIS

STEP 8. Voltage measurement at the A-02 ASC-ECU
connector

ZC601292 0002

ASC-ECU

MB991997

Check harness

A-02 ASC-ECU
harness connector

(1)

Disconnect the ASC-ECU connector, connect special tool
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 circuit
power supply terminal (signal terminal) No. 34 and the body
ground.

OK: Approximately battery voltage

Q:Is the check result normal?

YES:

Go to Step 11.

NO:

Go to Step 9.

STEP 9. Connector check: A-02 ASC-ECU connector, A-59
wheel speed sensor <FR> connector

Q:Is the check result normal?

YES:

Go to Step 10.

NO:

Repair the defective connector.

STEP 10. Wiring harness check between A-02 ASC-ECU
connector terminal No. 34/33 and A-59 wheel speed sensor
<FR> connector terminal No. 1/2

｠

Check for the open circuit in the wheel speed sensor <FR>
circuit.

Q:Is the check result normal?

YES:

Replace the wheel speed sensor.

NO:

Repair the wiring harness.

STEP 11. Check for wheel speed sensor as a single unit
Refer to P.35C-197.

Q:Is the check result normal?

YES:

Go to Step 12.

NO:

Replace the wheel speed sensor.

STEP 12. Check whether the diagnostic trouble code is
reset.

(1)

Erase the diagnostic trouble code.

(2)

Drive the vehicle at 12mph (20 km/h) or more.

NOTE:

The ABS warning light does not turn OFF in some

cases unless the vehicle runs at 12mph (20 km/h) or
higher.

35C-22

ACTIVE SKID CONTROL SYSTEM (ASC)

DIAGNOSIS