Mitsubishi Outlander XL. Manual - part 654

Q:Is DTC C1015 set?

YES:

 Replace the ASC-ECU.

NO:

 Intermittent malfunction (GROUP 00 - How to Cope with

Intermittent Malfunction P.00-15).

DTC C1020: Abnormality in RL wheel speed sensor circuit

M13506100012USA0000010000

Wheel Speed Sensor Circuit

ASC-ECU

FRONT 
WHEEL 
SPEED 
SENSOR
(LH)

FRONT 
WHEEL 
SPEED 
SENSOR
(RH)

REAR 
WHEEL 
SPEED 
SENSOR
(LH)

REAR 
WHEEL 
SPEED 
SENSOR
(RH)

If there is any problem in the CAN bus lines, an incorrect
diagnostic trouble code may be set. Prior to this diagnosis,
diagnose the CAN bus lines. (Refer to GROUP 54D, Trouble
code diagnosis P.54D-17).

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.

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-23

DIAGNOSIS

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 (Refer to 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. C1020 set?

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.03: RL 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.

35C-24

ACTIVE SKID CONTROL SYSTEM (ASC)

DIAGNOSIS

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

ZC601293 0004

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. 36/the ground terminal
No. 37 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. 36 or 37):

 Go to Step

7.

STEP 5. Connector check: A-02 ASC-ECU connector, C-125
intermediate connector, D-114 wheel speed sensor <RL>
connector

Q:Is the check result normal?

YES:

 Go to Step 6.

NO:

 Repair the defective connector.

STEP 6. Wiring harness check between A-02 ASC-ECU
connector terminal No. 36/37 and D-114 wheel speed sensor
<RL> connector terminal No. 1/2

｠

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

Q:Is the check result normal?

YES:

 Replace the wheel speed sensor <RL>.

NO:

 Repair the wiring harness.

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-25

DIAGNOSIS

STEP 7. Resistance measurement at A-02 ASC-ECU
connector

ZC601293 0005

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. 36/the ground terminal No. 37
and the body ground

OK: No continuity

Q:Is the check result normal?

YES:

 Go to Step 10.

NO (Not normal at the terminal No. 36 or 37):

 Go to Step

8.

STEP 8. Connector check: A-02 ASC-ECU connector, D-114
wheel speed sensor <RL> connector

Q:Is the check result normal?

YES:

 Go to Step 9.

NO:

 Repair the defective connector.

STEP 9. Wiring harness check between A-02 ASC-ECU
connector terminal No. 36/37 and D-114 wheel speed sensor
<RL> connector terminal No. 1/2

｠

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

Q:Is the check result normal?

YES:

 Replace the wheel speed sensor <RL>.

NO:

 Repair the wiring harness.

35C-26

ACTIVE SKID CONTROL SYSTEM (ASC)

DIAGNOSIS