Mitsubishi Lancer (4A9 engine). Manual — part 71

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-137

Code No. U1003 G and yaw rate sensor bus-off

G and Yaw Rate Sensor Circuit

G AND YAW RATE SENSOR

ASC-ECU

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

ACB02567

AC612691

AO

Connector: A-58 <LHD>

A-58 (B)

AC701238 AF

Connector: A-58 <RHD>

A-58 (B)

AC612705

Connector: C-137 <LHD>

CG

C-137 (B)

AC701122

Connector: C-137 <RHD>

BL

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-138

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.

• Do not drop or shock the G and yaw rate sen-

sor.

• When the G and yaw rate sensor is replaced,

always carry out calibration to make ASC-
ECU learn the neutral point (Refer to

P.35C-

182

).

• 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
The G and yaw rate sensor outputs the signal to
ASC-ECU via the special CAN bus lines.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set when the communication
error occurs in the exclusive CAN bus communica-
tion between the ASC-ECU and the G and yaw rate
sensor.

PROBABLE CAUSES

• Wiring harness or connector failure for the spe-

cial CAN bus lines between ASC-ECU and the G
and yaw rate sensor

• Malfunction of the G and yaw rate sensor

• ASC-ECU malfunction

• Connector disconnected or improperly connected

• Stretched or broken wires

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 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 diagnosis code No. U1003 set?

YES :

Go to Step 3.

NO :

This diagnosis is complete.

STEP 3. Connector check: A-58 ASC-ECU
connector, C-137 G and yaw rate sensor
connector

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Repair the connector, and then go to Step 7.

STEP 4. Wiring harness check between A-58
ASC-ECU connector terminal No. 18 and C-137 G
and yaw rate sensor connector terminal No. 3 as
well as between A-58 ASC-ECU connector
terminal No. 19 and C-137 G and yaw rate sensor
connector terminal No. 2

• Check the communication circuit for open and

short circuit.

Q: Is the check result normal?

YES :

Go to Step 5.

NO :

Repair the wiring harness, and then go to
Step 7.

STEP 5. Diagnosis code recheck

Q: Is diagnosis code No. U1003 set?

YES :

Replace the G and yaw rate sensor (Refer

to

P.35C-189

). Then go to Step 6.

NO :

Intermittent malfunction (Refer to GROUP
00

− How to Use Troubleshooting/How to

Cope with Intermittent Malfunctions ).

STEP 6. Diagnosis code recheck
Erase the diagnosis code.

Q: Is diagnosis code No. U1003 set?

YES :

Replace the hydraulic unit (integrated with

ASC-ECU) (Refer to

P.35C-185

). Then go

to Step 7.

NO :

This diagnosis is complete.

STEP 7. Diagnosis code recheck
Erase the diagnosis code.

Q: Is diagnosis code No. U1003 set?

YES :

Return to Step 1.

NO :

This diagnosis is complete.

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-139

Code No. U1415 Variant coding not implemented

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 diagnosis code No.U1415 is set in

ASC-ECU, the diagnosis code may also be set
in ETACS-ECU. When the diagnosis code is
set in ETACS-ECU, carry out the diagnosis of
the diagnosis code for ETACS-ECU first.

• 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 receives the vehicle information stored in
the ETACS-ECU via CAN bus lines.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set when the variant coding
for ETACS-ECU has not been implemented.

PROBABLE CAUSES

• Variant coding for ETACS-ECU has not been

implemented.

• ASC-ECU malfunction

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 ). On

completion, go to Step 4.

STEP 2. M.U.T.-III other system diagnosis code
Use M.U.T.-III to check that the diagnosis code
No.B222C is set in the ETACS-ECU.

Q: Is the diagnosis code set?

YES :

Troubleshoot the relevant diagnosis code,

and then go to Step 4.

NO :

Go to Step 3.

STEP 3. Check whether the diagnosis code is
reset.
(1) Erase the diagnosis code.
(2) Turn the ignition switch to the "OFF" position.
(3) Turn the ignition switch to the "ON" position.
(4) Check that the ABS warning lamp goes out.

NOTE: If the diagnosis code No.U1415 is not
deleted, the ABS warning lamp keeps illuminat-
ing.

Q: Is the diagnosis code No.U1415 set?

YES :

Replace the hydraulic unit (integrated with

ASC-ECU) (Refer to

P.35C-185

), and then

go to Step 4.

NO :

Intermittent malfunction (Refer to GROUP
00

− How to Use Troubleshooting/How to

Cope with Intermittent Malfunctions ).

STEP 4. Check whether the diagnosis code is
reset.
(1) Erase the diagnosis code.
(2) Turn the ignition switch to the "OFF" position.
(3) Turn the ignition switch to the "ON" position.
(4) Check that the ABS warning lamp goes out when

the ignition switch is turned to the "ON" position.
NOTE: If the diagnosis code No.U1415 is not
deleted, the ABS warning lamp keeps illuminat-
ing.

Q: Is the diagnosis code No.U1415 set?

YES :

Return to Step 1.

NO :

This diagnosis is complete.

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-140

Code No. U1417 Variant coding value invalid (includes faulty installation)

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 ).

• If diagnosis code No.U1417 is set in ASC-

ECU, always diagnose the CAN bus lines. If
there is any fault in the CAN bus lines, an
incorrect diagnosis code may be set. In this
case, the set diagnosis code is not highly reli-
able.

• Before replacing the ECU, ensure that the

communication circuit is normal.

• When diagnosis code No.U1417 is set in ASC-

ECU, the diagnosis code may also be set in
ETACS-ECU. When the diagnosis code is set
in ETACS-ECU, carry out the diagnosis of the
diagnosis code for ETACS-ECU first.

• 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 receives the vehicle information stored in
the ETACS-ECU via CAN bus lines.

DIAGNOSIS CODE SET CONDITIONS
ASC-ECU communicates with ETACS-ECU via CAN
bus lines. This diagnosis code is set when the vehi-
cle information received from the ETACS-ECU is
invalid.

PROBABLE CAUSES

• Malfunction of ETACS-ECU

• Malfunction of engine ECU

• ETACS-ECUs have been interchanged between

two vehicles.

• Malfunction of ASC-ECU

• External noise interference

• ASC-ECUs have been interchanged between two

vehicles.

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 diagnosis code No.U1417 set?

YES :

Go to Step 3.

NO :

This diagnosis is complete.

STEP 3. M.U.T.-III other system diagnosis code
Use M.U.T.-III to check whether the any diagnosis
code related to the vehicle information is set or not
by ETACS-ECU or engine-ECU.

Q: Is the diagnosis code set?

YES :

Troubleshoot for the relevant diagnosis

code.

NO :

Go to Step 4.

STEP 4. ETACS-ECU coding data check
Refer to GROUP 00

− Precautions 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 7.

STEP 5. Engine ECU coding data check
Refer to GROUP 00

− Precautions before Service/

Coding List .

Q: Is the check result normal?

YES :

Go to Step 6.

NO :

Replace the engine ECU (Refer to GROUP
13A

− engine ECU <4A9>, GROUP 13B −

engine ECU <4B1>, GROUP 13F

− engine

ECU <4J1> or GROUP 13C

− engine ECU

<4N1>), and then go to Step 7.

STEP 6. Check the part number of ETACS-ECU
Check the part number of ETACS-ECU.

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

Replace the ETACS-ECU (Refer to GROUP
54A

− ETACS-ECU ), and then go to Step 7.