Mitsubishi Lancer Evolution X. Manual - part 189

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-221

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

STEP 1. Using scan tool MB991958, diagnose the CAN bus
lines.
Using scan tool MB991958, 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 −

Troubleshooting

P.54C-15

.) After repairing the CAN

bus line, go to Step 2.

STEP 2. DTC recheck after repairing the CAN bus line
Q: Is DTC U0251, U0440 or U0435 set?

YES : Go to Step 3.
NO : This diagnosis is complete.

STEP 3. Diagnostic trouble code check of other system
using scan tool MB991958
Using scan tool MB991958, check if a diagnostic trouble code
is set in AWC-ECU.
Q: Is other DTC set?

YES : Troubleshoot the relevant diagnostic trouble code,

and then go to Step 8.

NO : Go to Step 4.

STEP 4. Connector check: A-05 ASC-ECU connector, C-46
AWC-ECU connector, C-47 intermediate connector, C-50
joint connector
Q: Is the check result normal?

YES : Go to Step 5.
NO : Repair the connector, and then go to Step 8.

STEP 5. Wiring harness check between A-05 ASC-ECU
connector terminal No. 18 and C-46 AWC-ECU connector
terminal No. 9, between A-05 ASC-ECU connector terminal
No. 19 and C-46 AWC-ECU connector terminal No. 10

• Open or short circuit check of communication circuit

Q: Is the check result normal?

YES : Go to Step 6.
NO : Repair the wiring harness, and then go to Step 8.

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-222

STEP 6. Check whether the DTC is reset.
Q: Are DTC U0251, U0440, and U0435 set?

YES : Replace the AWC-ECU. (Refer to GROUP 22A −

Manual Transaxle, AWC-ECU

P.22A-133

.) Then go to

Step 7.

NO : Intermittent malfunction. (Refer to GROUP 00 − How

to Cope with Intermittent Malfunction

P.00-15

STEP 7. Check whether the DTC is reset.
Q: Is DTC U0251, U0440 or U0435 set?

YES : Replace the hydraulic unit (incorporates in

ASC-ECU). (Refer to

P.35C-298

.) Then go to Step 8.

NO : The procedure is complete.

STEP 8. Check whether the DTC is reset.
Q: Is DTC U0251, U0440 or U0435 set?

YES : Return to Step 1.
NO : The procedure is complete.

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-223

DTC U1003: G and yaw rate sensor bus-off

G AND YAW
RATE SENSOR

JOINT
CONNECTOR (7)

AWC-ECU

ASC-ECU

G and Yaw Rate Sensor Circuit

AC708948

Connector: A-05

A-05 (B)

AC708951AG

C-38 (B)

Connector: C-38

DIAGNOSIS

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ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-224

CAUTION

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

rect diagnostic trouble code may be set. Prior to this
diagnosis, diagnose the CAN bus lines.

• Whenever the ECU is replaced, ensure that the CAN

bus lines are normal.

• Do not drop the G and yaw rate sensor or subject it to a

shock.

• When the G and yaw rate sensor is replaced, always

perform the calibration to make ASC-ECU learn the
neutral point (Refer to

P.35C-287

• When the hydraulic unit (integrated with ASC-ECU) is

replaced, after turning the ignition switch ON and OFF
(vehicle information from ETACS-ECU is registered),
always perform the calibration of steering wheel sen-
sor, G and yaw rate sensor, brake fluid pressure sen-
sor, cut valve, and inlet valve (Refer to

, and

CIRCUIT OPERATION

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

DTC SET CONDITIONS

This diagnostic trouble code is set when ASC-ECU cannot
receive the signal sent from the G and yaw rate sensor.

PROBABLE CAUSES

• Wiring harness or connector failure in special CAN bus lines

between ASC-ECU and G and yaw rate sensor