Mitsubishi Lancer (4A9 engine). Manual — part 73

AC612705

Connector: C-01 <LHD>

BK

AC701122 BN

Connectors: C-01, C-16 <RHD>

C-01

C-16

AC612706

Connector: C-16 <LHD>

AO

AC612707

AH

Connector: C-116 <LHD>

C-116 (B)

AC701089

Connector: C-116 <RHD>

C-116 (B)

AF

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-145

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.

OPERATION

• When the parking brake switch is turned ON, the

combination meter terminal No.4 is earthed, and
the brake warning lamp illuminates.

• When reduction of the brake fluid amount is

detected, the brake fluid level switch is turned
from ON to OFF. ETACS-ECU monitors the brake
fluid level switch, and instructs the combination
meter via the CAN bus line to illuminate the brake
warning lamp.

PROBABLE CAUSES

• The brake pad thickness is at the limit value or

less.

• The brake fluid amount is at the "LOWER" level

or lower.

• Poor adjustment of the parking brake lever

• Damaged wiring harness and connectors

• Parking brake switch malfunction

• Malfunction of brake fluid level switch

• Combination meter malfunction

• Malfunction of ETACS-ECU

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 2.

NO :

Repair the CAN bus lines (Refer to GROUP
54C

− CAN Bus Diagnostics Table ).

STEP 2. M.U.T.-III diagnosis code
Use M.U.T.-III to check that the diagnosis code is set
in the combination meter and ETACS-ECU.

Q: Is the diagnosis code set?

YES :

Carry out the diagnosis for the diagnosis

code.

NO :

Go to Step 3.

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-146

STEP 3. Brake fluid level check
Check that the brake fluid is filled up to the "MIN"
level or higher.

Q: Is the check result normal?

YES :

Go to Step 5.

NO :

Go to Step 4.

STEP 4. Brake pad check
Refer to GROUP 35A

− On-vehicle Service, Brake

Pad Check .

Q: Is the check result normal?

YES :

Fill the brake fluid up to the "MAX" level.

Then go to Step 17.

NO :

Replace the brake pad (Refer to GROUP
35A

− On-vehicle Service/Brake Pad

Replacement <Except 4B11>, <4B11>).
Then go to Step 17.

STEP 5. Brake fluid level switch check
Refer to GROUP 35A

− On-vehicle Service/Brake

Fluid Level Switch Check .

Q: Is the check result normal?

YES :

Go to Step 6.

NO :

Replace the reservoir tank assembly (Refer
to GROUP 35A

− Master Cylinder Assembly

and Brake Booster Assembly <Except
4B11>, <4B11>). Then go to Step 17.

STEP 6. Connector check: A-07 brake fluid level
switch connector, C-312 ETACS-ECU connector

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

Repair the damaged connector.

STEP 7. Measure the voltage at A-07 brake fluid
level switch connector.
(1) Disconnect the connector, and measure at the

wiring harness side.

(2) Turn the ignition switch to the ON position.
(3) 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 :

Go to Step 8.

STEP 8. Measure the voltage at the C-312 ETACS-
ECU connector.

CAUTION

With the C-312 ETACS-ECU connector kept con-
nected, disconnect the A-07 brake fluid level
switch connector.
(1) Turn the ignition switch to the ON position.
(2) Measure the voltage between terminal No. 1 and

the body earth by backprobing.

OK: Approximately system voltage

Q: Is the check result normal?

YES :

Check the wiring harness between the C-

312 ETACS-ECU connector terminal No. 1
and the A-07 brake fluid level switch
connector terminal No. 1.

NO :

Replace the ETACS-ECU. (Refer to
GROUP 54A

− ETACS .) Then go to Step

17.

STEP 9. Wiring harness check: between A-07
brake fluid level switch connector and body earth
Check for open circuit in the harness wire between
A-07 brake fluid level switch connector terminal No. 2
and body earth.

Q: Is the check result normal?

YES :

Go to Step 10.

NO :

Repair the wiring harness.

STEP 10. Parking brake lever stroke check
Refer to GROUP 36

− On-vehicle Service/Parking

Brake Lever Stroke Check and Adjustment .

Q: Is the check result normal?

YES :

Go to Step 11.

NO :

Adjust the parking brake lever stroke. (Refer
to GROUP 36

− On-vehicle Service/Parking

Brake Lever Stroke Check and Adjustment
.) Then go to Step 17.

STEP 11. Parking brake switch check
Refer to GROUP 36

− On-vehicle Service/Parking

Brake Switch Check .

Q: Is the check result normal?

YES :

Go to Step 12.

NO :

Replace the parking brake switch. (Refer to
GROUP 36

− Parking Brake Lever .) Then

go to Step 17.

STEP 12. Connector check: C-116 parking brake
switch connector

Q: Is the check result normal?

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-147

YES :

Go to Step 13.

NO :

Repair the damaged connector.

STEP 13. Measure the voltage at C-116 parking
brake switch connector.
(1) Disconnect the connector, and measure at the

wiring harness side.

(2) Turn the ignition switch to the ON position.
(3) 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 16.

NO :

Go to Step 14.

STEP 14. Connector check: C-01 combination
meter connector, C-16 intermediate connector

Q: Is the check result normal?

YES :

Go to Step 15.

NO :

Repair the damaged connector.

STEP 15. check the wiring harness between the
C-01 combination meter connector terminal No. 4
and the C-116 parking brake switch connector
terminal No. 1.

• Check for short circuit.

Q: Is the check result normal?

YES :

Go to Step 16

NO :

Repair the wiring harness.

STEP 16. Retest the system.

Q: Does the brake warning lamp turn ON and OFF

normally according to the parking brake lever
operation?
YES :

Intermittent malfunction (Refer to GROUP

00

− How to Use Troubleshooting/How to

Cope with Intermittent Malfunctions .)

NO :

Replace the combination meter assembly.
(Refer to GROUP 54A

− Combination Meter

.) Then go to Step 17.

STEP 17. Retest the system.

Q: Does the brake warning lamp turn ON and OFF

normally according to the parking brake lever
operation?
YES :

This diagnosis is complete.

NO :

Return to Step 1.

Inspection Procedure 4: ABS warning lamp does not illuminate when ignition switch is turned to the
ON position (engine stopped).

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 ).

• Before replacing the ECU, ensure that the

communication circuit is 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 sends the illumination request signal

of the ABS warning lamp to the combination
meter through ETACS-ECU via CAN communica-
tion.

• ASC-ECU illuminates the ABS warning lamp via

ETACS-ECU for approximately 3 seconds for
valve check with the ignition switch turned to the
ON position.

COMMENTS ON TROUBLE SYMPTOM
This may be caused by faults in the CAN bus line,
ETACS-ECU, combination meter or ASC-ECU.

PROBABLE CAUSES

• Damaged wiring harness and connectors

• Malfunction of ETACS-ECU

• Combination meter malfunction

• ASC-ECU malfunction

• Malfunction of coding data for ETACS-ECU

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-148

DIAGNOSIS PROCEDURE

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

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the CAN bus lines. (Refer to GROUP
54C

− CAN Bus Diagnostics Table .)

STEP 2. M.U.T.-III diagnosis code
Use M.U.T.-III to check the diagnosis code for the
ASC system. (Refer to

P.35C-16

.)

Q: Is the diagnosis code set?

YES :

Carry out the diagnosis for the diagnosis

code. (Refer to

P.35C-16

.)

NO :

Go to Step 3.

STEP 3. Actuator test
Perform the actuator test No. 07 of the combination
meter system, and check if the ABS warning lamp
illuminates (Refer to GROUP 54A

− Combination

Meter/Actuator Test Table ).

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Diagnose the combination meter. (Refer to
GROUP 54A

− Combination Meter/Trouble

Symptom Chart .) Then go to Step 8.

STEP 4. ETACS-ECU coding data check
Use M.U.T.-III to check if coding data stored in
ETACS-ECU is normal. (Refer to GROUP 00

− Pre-

cautions before Service/Coding List .)

Q: Is the check result normal?

YES :

Go to Step 5.

NO :

Replace the ETACS-ECU (Refer to GROUP
54A

− ETACS-ECU ), and then go to Step 8.

STEP 5. M.U.T.-III diagnosis code for other
systems
Using M.U.T.-III, check that the diagnosis code
No.U0141 is set by the combination meter system.

Q: Is the diagnosis code set?

YES :

Diagnose the combination meter. (Refer to

GROUP 54A

− Combination Meter/

Troubleshooting .) Then go to Step 8.

NO :

Go to Step 6.

STEP 6. M.U.T.-III diagnosis code for other
systems
Using M.U.T.-III, check that the diagnosis code
No.U0121 is set by the ETACS system.

Q: Is the diagnosis code set?

YES :

Troubleshoot the ETACS-ECU (Refer to

GROUP 54A

− ETACS/Troubleshooting ),

and then go to Step 8.

NO :

Go to Step 7.

STEP 7. Retest the system.

Q: Does the ABS warning lamp turn ON and OFF

normally?
YES :

Intermittent malfunction (Refer to GROUP

00

− How to Use Troubleshooting/How to

Cope with Intermittent Malfunctions .)

NO :

Replace the hydraulic unit (integrated with
ASC-ECU) (Refer to

P.35C-185

), and then

go to Step 8.

STEP 8. Retest the system.

Q: Does the ABS warning lamp turn ON and OFF

normally?
YES :

This diagnosis is complete.

NO :

Return to Step 1.