Mitsubishi Lancer (4A9 engine). Manual - part 59

 

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Mitsubishi Lancer (4A9 engine). Manual - part 59

 

 

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-89

STEP 7. Resistance measurement at A-58 ASC-
ECU connector

AC606869FS

ASC-ECU

MB991997

Check harness

A-58 ASC-ECU
harness 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 ASC 
check harness (MB991997) to ASC-ECU.

(2) Disconnect the fusible link No.26.
(3) Measure the resistance between the terminal 

No.1 and the body earth.

OK: No continuity

Q: Is the check result normal?

YES : 

Replace the fusible link No.26. Then go to 

Step 11.

NO : 

The short circuit may be present in the 
power supply circuit. Repair the wiring 
harness between the A-58 ASC-ECU 
connector terminal No.1 and the fusible link 
No.26, and then replace the fusible link 
No.26. Then go to Step 11.

STEP 8. Voltage measurement at the A-58 ASC-
ECU connector

AC606869DI

ASC-ECU

MB991997

Check harness

A-58 ASC-ECU
harness 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 ASC 
check harness (MB991997) to ASC-ECU.

(2) Measure the voltage between the terminal No.1 

and the body earth.

OK: Approximately system voltage

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

The open circuit may be present in the 
power supply circuit. Repair the wiring 
harness between the A-58 ASC-ECU 
connector terminal No.1 and the fusible link 
No.26. Then go to Step 11.

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-90

STEP 9. Resistance measurement at A-58 ASC-
ECU connector

AC606869DJ

ASC-ECU

MB991997

Check harness

A-58 ASC-ECU
harness 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 ASC 
check harness (MB991997) to ASC-ECU.

(2) Measure the resistance between the terminal 

No.16 and the body earth, and between the 
terminal No.47 and the body earth.

OK: Continuity exists (2 

Ω or less)

Q: Is the check result normal?

YES : 

Go to Step 10.

NO : 

An open circuit may be present in the earth 
circuit. Repair the wiring harness between 
the A-58 ASC-ECU connector terminal 
No.16 and the body earth, and between the 
A-58 ASC-ECU connector terminal No.47 
and the body earth. Then go to Step 11.

STEP 10. Check whether the diagnosis code is 
reset.
(1) Erase the diagnosis code.
(2) Drive the vehicle at 20 km/h or higher.

NOTE: The ABS warning lamp does not turn OFF 
in some cases unless the vehicle runs at 20 km/h 
or higher.

Q: Is the diagnosis code No. C1073 set?

YES : 

Replace the hydraulic unit (integrated with 

ASC-ECU) (Refer to 

P.35C-185

). Then go 

to Step 11.

NO : 

Intermittent malfunction (Refer to GROUP 
00 

− How to Use Troubleshooting/How to 

Cope with Intermittent Malfunctions ).

STEP 11. Check whether the diagnosis code is 
reset.
(1) Erase the diagnosis code.
(2) Drive the vehicle at 20 km/h or higher.

NOTE: The ABS warning lamp does not turn OFF 
in some cases unless the vehicle runs at 20 km/h 
or higher.

Q: Is the diagnosis code No. C1073 set?

YES : 

Return to Step 1.

NO : 

This diagnosis is complete.

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-91

Code No. C2116 Low or high power supply voltage in pump motor

Solenoid Valve and Motor Power Source Circuit

MOTOR 
POWER 
SOURCE

SOLENOID 
VALVE 
POWER 
SOURCE

ASC-ECU

SOLENOID 
VALVE 
POWER 
SOURCE

MOTOR POWER 
SOURCE

Wire colour code 
B : Black     LG : Light green     G : Green     L : Blue     W : White     Y : Yellow     SB : Sky blue 
BR : Brown     O : Orange     GR : Grey     R : Red     P : Pink     V : Violet     PU : Purple     SI : Silver

SOLENOID VALVE

HYDRAULIC UNIT

MOTOR

FUSIBLE
LINK

27

FUSIBLE
LINK

26

ACB02566

AC612691

AO

Connector: A-58 <LHD>

A-58 (B)

AC701238 AF

Connector: A-58 <RHD>

A-58 (B)

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-92

CAUTION

• If there is any problem in the CAN bus lines, 

an incorrect diagnosis code may be set. Prior 
to this diagnosis, diagnose the CAN bus lines 
(Refer to GROUP 54C 

− CAN Bus Diagnostics 

Table ).

• 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 calibra-
tion of the steering wheel sensor, the G and 
yaw rate sensor and brake fluid pressure sen-
sor (Refer to 

P.35C-182

, 

P.35C-183

 and 

P.35C-

184

).

OPERATION

• ASC-ECU contains the power supply circuit (ter-

minal No.1) for the pump motor. The pump motor 
is energised by the motor switch, which is incor-
porated in ASC-ECU.

• The pump motor switch, which is incorporated in 

ASC-ECU, is always off unless the motor sole-
noid valve check is activated when the vehicle is 
started.

• ASC-ECU activates the pump motor by turning 

on the ECU built-in pump motor switch.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis codes will be set under the cases 
below:

• When the power supply voltage of the pump 

motor, which is not in operation, is abnormally low 
for a prolonged period

• When the power supply voltage of the pump 

motor, which is not in operation, is abnormally 
high for a prolonged period

PROBABLE CAUSES

Current trouble

• Fusible link malfunction

• Damaged wiring harness and connectors

• Abnormality in battery or alternator

• ASC-ECU malfunction

Past trouble

• Carry out diagnosis with particular emphasis on 

wiring harness and connector failures between 
the power supply circuit (A-58 ASC-ECU connec-
tor terminal No.1) to the ASC-ECU motor and the 
earth circuit (A-58 ASC-ECU connector terminal 
No.16 and 47). For diagnosis procedures, refer to 
How to treat past trouble (GROUP 00 

− How to 

Use Troubleshooting/How to Treat Past Trouble ).

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosis
Use 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 
54C 

− CAN Bus Diagnostics Table ). On 

completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting 
CAN bus lines

Q: Is the diagnosis code No. C2116 set?

YES : 

Go to Step 3.

NO : 

This diagnosis is complete.

STEP 3. Battery check
Refer to GROUP 54A 

− Battery Test .

Q: Is the battery in good condition?

YES : 

Go to Step 4.

NO : 

Replace the battery. Then go to Step 11.

STEP 4. Charging system check
Refer to GROUP 16 

− On−vehicle Service/Alternator 

Output Line Voltage Drop Test .

Q: Is the charging system in good condition?

YES : 

Go to Step 5.

NO : 

Repair or replace the charging system 
component(s). Then go to Step 11.

STEP 5. Connector check: A-58 ASC-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 6.

NO  : 

Repair the defective connector. Then go to 
Step 11.

STEP 6. Fusible link check: Check the fusible link 
No.26.
Visually check for open circuit in the fusible link 
No.26.

Q: Is the check result normal?

YES : 

Go to Step 8.

NO : 

Go to Step 7.

 

 

 

 

 

 

 

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