Mitsubishi Outlander XL. Manual - part 659

Q:Is DTC C101C set?

YES:

 Replace the ASC-ECU.

NO:

 Intermittent malfunction (GROUP 00 - How to Cope with

Intermittent Malfunction P.00-15).

DTC C1027: Abnormality in RL wheel speed sensor signal

M13506100016USA0000010000

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-43

DIAGNOSIS

DTC SET CONDITIONS
ASC-ECU monitors the signals from each wheel speed sensor
while the vehicle is being driven. If any fault below is found in
these sensor signals, ASC-ECU will set the relevant diagnostic
trouble code.

｠

Irregular change in the wheel speed sensor signal

｠

Wheel speed sensor signal continuously indicates high value.

PROBABLE CAUSES

Current trouble

｠

Excessive  gap  between  the  wheel  speed  sensor  and  the
wheel speed detection encoder

｠

Adhesion of foreign materials on the wheel speed sensor

｠

Adhesion of foreign materials on the wheel speed detection
encoder

｠

Wheel bearing malfunction

｠

Malfunction of wheel speed sensor

｠

Damaged wiring harness and connectors

｠

External noise interference

｠

Improper installation of the wheel speed sensor

｠

Deformation of the wheel speed detection encoder

｠

ASC-ECU malfunction

｠

Disturbance  of  magnetization  pattern  for  wheel  speed
detection encoder

Past trouble

｠

When the diagnostic trouble code No. C1020 is also set, 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).

｠

When the diagnostic trouble code No. C1020 is not set, the
following conditions may be present:

｠

Right or/and left wheels are rotated.

｠

Unstable vehicle attitude

｠

External noise interference

｠

Vehicle ran with the parking brake applied.

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?

35C-44

ACTIVE SKID CONTROL SYSTEM (ASC)

DIAGNOSIS

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 DTC C1027 set?

YES:

 Go to Step 3.

NO:

 The procedure is complete.

STEP 3. M.U.T.-III diagnostic trouble code
Check that the diagnostic trouble code C1020 is also set.

Q:Is DTC C1020 also set?

YES:

 Perform the diagnosis for the diagnostic trouble

code C1020. (Refer to P.35C-23.)

NO:

 Go to Step 4.

STEP 4. Check for wheel speed sensor installation
Check  how  the  wheel  speed  sensor  <RL>  is  installed
(Disconnection  of  wheel  speed  sensor,  loose  mounting  bolt,
etc.).

Q:Is the check result normal?

YES:

 Go to Step 5.

NO:

 Reinstall the wheel speed sensor <RL> correctly.

STEP 5. Check for wheel speed sensor as a single unit

Q:Is the check result normal?

YES:

 Go to Step 6.

NO:

 Replace the wheel speed sensor.

STEP 6. Check for wheel bearing looseness

NOTE: 

Loose wheel bearing may increase the gap between the

wheel speed sensor and the wheel speed detection magnet
encoder. Check the wheel bearing <RL> for looseness. <Refer
to GROUP 27A - On-vehicle Service P.27A-4.(FWD) or GROUP 27B
- On-vehicle Service P.27B-15.(AWD)>

Q:Is the check result normal?

YES:

 Go to Step 7.

NO:

 Replace the rear wheel hub assembly.

ACTIVE SKID CONTROL SYSTEM (ASC)

35C-45

DIAGNOSIS

STEP 7. Check of wheel speed detection encoder

ZC601558 0000

Magnetic 
encoder

Rear hub 
assembly

Rear wheel bearing

Ball bearing

Rear hub 
assembly

Magnetic 
encoder

<FWD>

<AWD>

Check  the  encoder  for  adhesion  of  foreign  materials  or
deformation.

Q:Is the check result normal?

YES:

 Go to Step 8.

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.

NO (Deformation):

 Replace the rear wheel hub assembly.

STEP 8. 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 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 9.

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

 Go to Step

10.

35C-46

ACTIVE SKID CONTROL SYSTEM (ASC)

DIAGNOSIS