Mitsubishi Colt Ralliart. Manual — part 616

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-9

OPERATION

• The wheel speed sensor is a kind of a pulse gen-

erator. It consists of magnetic encoders (a plate
on which north and south pole sides of the mag-
nets are arranged alternately) for detecting the
wheel speed which rotates at the same speed of
the wheels and speed sensors. This sensor out-
puts 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.

DIAGNOSIS CODE SET CONDITIONS

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

PROBABLE CAUSES

Current trouble

• Damaged wiring harness and connectors

• Malfunction of the wheel speed sensor

• ASC-ECU malfunction

Past trouble

• Carry out diagnosis with particular emphasis on

wiring harness and connector failures between
ASC-ECU and wheel speed sensor. For diagno-
sis procedures, refer to How to treat past trouble
(GROUP 00

− How to Use Troubleshoot-

ing/Inspection Service Points

P.00-13

).

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III 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

− Troubleshooting

P.54D-13

.) On

completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting
CAN bus lines

Q: Is the diagnosis code No. C1200, C1205, C1210 or

C1215 set?
YES :

Go to Step 3.

NO :

This diagnosis is complete.

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

P.35B-72

.)

• (When the code No. C1200 is set) Item 01: FR

wheel speed sensor

• (When the code No. 1205 is set) Item 02: FL

wheel speed sensor

• (When the code No. 1210 is set) Item 03: RR

wheel speed sensor

• (When the code No. C1215 is set) Item 04: RL

wheel speed sensor

Q: Is the check result normal?

YES :

Intermittent malfunction (Refer to GROUP

00

− How to Cope with Intermittent

Malfunction

P.00-13

.)

NO :

Go to Step 4.

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-10

STEP 4. Voltage measurement: A-05 ASC-ECU
connector

(1) Disconnect the connector, connect the ABS

check harness (Special tool: MB991984) to the
harness-side connector, and measure the voltage
at the special tool connector side.
NOTE: . Do not connect the special tool to
ASC-ECU.

(2) Ignition switch: ON
(3) Measure the voltage between the power supply

and signal terminals in the wheel speed sensor
circuit and body earth.

OK: 0 V

Q: Is the check result normal?

YES :

Go to Step 5.

NO (Not normal at the terminal No. 29 or 28) :

Go

to Step 6.

NO (Not normal at the terminal No. 34 or 13) :

Go

to Step 8.

NO (Not normal at the terminal No. 30 or 8) :

Go to

Step 10.

NO (Not normal at the terminal No. 11 or 10) :

Go

to Step 12.

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601085AB

MB991984

Check connector

ASC-ECU

ASC-ECU harness connector

Diagnosis code No.

Checking terminal
Power
supply
terminal

Signal
terminal

C1200

No. 29

No. 28

C1205

No. 34

No. 13

C1210

No. 30

No. 8

C1215

No. 11

No. 10

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-11

STEP 5. Measure the resistance at A-05 ASC-ECU
connector.

(1) Disconnect the connector, connect the ABS

check harness (Special tool: MB991984) to the
harness-side connector, and measure the voltage
at the special tool connector side.
NOTE: Do not connect the special tool to
ASC-ECU.

(2) Measure the resistance between the power

supply and signal terminals in the wheel speed
sensor circuit and body earth.

OK: No continuity

Q: Is the check result normal?

YES :

Go to Step 14.

NO (Not normal at the terminal No. 29 or 28) :

Go

to Step 6.

NO (Not normal at the terminal No. 34 or 13) :

Go

to Step 8.

NO (Not normal at the terminal No. 30 or 8) :

Go to

Step 10.

NO (Not normal at the terminal No. 11 or 10) :

Go

to Step 12.

STEP 6. Connector check: A-05 ASC-ECU
connector, A-29 wheel speed sensor <FR>
connector

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

Repair the damaged connector.

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601085AC

MB991984

ASC-ECU

Check connector

ASC-ECU harness connector

Diagnosis code No.

Checking terminal
Power
supply
terminal

Signal
terminal

C1200

No. 29

No. 28

C1205

No. 34

No. 13

C1210

No. 30

No. 8

C1215

No. 11

No. 10

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601084

Connector: A-29

AB

Harness
side

A-29(black)

Main

Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-12

STEP 7. Wiring harness inspection: between
A-05 ASC-ECU connector terminal No. 29, 28 and
A-29 wheel speed sensor <FR> connector
terminal No. 2, 1.

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

Q: Is the check result normal?

YES :

Replace the wheel speed sensor <FR>.

NO :

Repair the wiring harness.

STEP 8. Connector check: A-05 ASC-ECU
connector, A-06 wheel speed sensor <FL>
connector

Q: Is the check result normal?

YES :

Go to Step 9.

NO :

Repair the damaged connector.

STEP 9. Check the harness wire between A-05
ASC-ECU connector terminal No. 34, 13 and A-06
wheel speed sensor <FL> connector terminal No.
2, 1.

Check for short circuit in wheel speed sensor <FL>
circuit.

Q: Is the check result normal?

YES :

Replace the wheel speed sensor <FL>.

NO :

Repair the wiring harness.

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601084

Connector: A-29

AB

Harness
side

A-29(black)

AC601083

Connectors: A-05, A-06

AC

A-05(Black)

A-05:
Harness side

A-06: Harness side

A-06 (Black)

AC601083

Connectors: A-05, A-06

AC

A-05(Black)

A-05:
Harness side

A-06: Harness side

A-06 (Black)

Main

Index

Group

TOC