Mitsubishi Colt Ralliart. Manual — part 450

TROUBLESHOOTING

POWER STEERING

37-67

Code No.U1122 ABS-ECU failure information

CAUTION

• If the electric power steering-ECU sets diagnosis code No.U1122, diagnose the CAN bus lines. If

there is any fault in the CAN bus lines, an incorrect diagnosis code may be set.

•

ENGINE-CVT-ECU

DIAGNOSIS
CONNECTOR

FRONT SIDE

COMBINATION
METER

ABS-ECU

EPS-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

CAN Communication Circuit

Whenever the ECU is replaced, ensure that the communication circuit is normal.

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TROUBLESHOOTING

POWER STEERING

37-68

TROUBLE JUDGMENT

The electric power steering-ECU receives vehicle
speed data (wheel speed sensor data) from the
ABS-ECU through the CAN bus lines. If the ECU
receives vehicle speed data (wheel speed sensor
data) containing failure information twice, diagnosis
code U1122 will be set.

COMMENTS ON TROUBLE SYMPTOM

The M.U.T.-III shows a diagnosis code status as

active

• The wheel speed sensor system (of the

ABS-ECU), the ABS-ECU or the electric power
steering-ECU may be defective.

The M.U.T.-III shows a diagnosis code status as

stored

• Carry out diagnosis by referring to GROUP 00,

How to Use Troubleshooting/Inspection Service
Points

− How to treat past trouble

P.00-13

. Carry

out diagnosis with particular emphasis on con-
nector(s) or wiring harness in the CAN bus lines
between the ABS-ECU and the electric power
steering-ECU.

NOTE: For a The M.U.T.-III shows a diagnosis code

status as stored, you can not find it by the
M.U.T.-III CAN bus diagnostics even if there is
any failure in CAN bus lines. In this case, refer to
GROUP 00, How to Use Troubleshooting/Inspec-
tion Service Points-How to Cope with Intermittent
Malfunction

P.00-13

and check the CAN bus

lines. You can narrow down the possible cause of
the trouble by referring to the diagnosis code,
which is set regarding the CAN communica-
tion-linked ECUs (Refer to GROUP 54D, CAN
Bus Line Diagnostic Flow

P.54D-7

).

PROBABLE CAUSES

• Defective harness wire(s) or connector(s)

• Malfunction of the ABS-ECU

• Malfunction of the electric power steering-ECU

DIAGNOSIS PROCEDURE

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

AC206895

AC

Diagnosis

connector

MB991827

MB991824

MB991910

CAUTION

Before connecting or disconnecting the
M.U.T.-III, turn the ignition switch to the "LOCK"
(OFF) position.
(1) Connect M.U.T.-III to the 16-pin diagnosis

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF)

position.

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the CAN bus line (Refer to GROUP
54D, Diagnosis

P.54D-13

).

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TROUBLESHOOTING

POWER STEERING

37-69

STEP 2. M.U.T.-III other system diagnosis code

AC206895

AC

Diagnosis

connector

MB991827

MB991824

MB991910

CAUTION

Before connecting or disconnecting the
M.U.T.-III, turn the ignition switch to the "LOCK"
(OFF) position.
Check again if the diagnosis code is set.
(1) Turn the ignition switch to the "ON" position.
(2) Erase the diagnosis code.
(3) Turn the ignition switch to the "LOCK" (OFF)

position.

(4) Turn the ignition switch to the "ON" position.
(5) Check that an ABS system diagnosis code is set.
(6) Turn the ignition switch to the "LOCK" (OFF)

position.

Q: Is the diagnosis code set?

YES :

Diagnose the ABS system (Refer to

GROUP 35B, Troubleshooting

P.35B-7

).

NO :

Go to Step 3.

STEP 3. Check whether the diagnosis code is
reset

AC206895

AC

Diagnosis

connector

MB991827

MB991824

MB991910

CAUTION

Before connecting or disconnecting the
M.U.T.-III, turn the ignition switch to the "LOCK"
(OFF) position.
Check again if the diagnosis code is set.
(1) Turn the ignition switch to the "ON" position.
(2) Erase the diagnosis code.
(3) Turn the ignition switch to the "LOCK" (OFF)

position.

(4) Turn the ignition switch to the "ON" position.
(5) Recheck whether diagnosis code U1122 is set.
(6) Turn the ignition switch to the "LOCK" (OFF)

position.

Q: Is the diagnosis code set?

YES :

Replace the electric power steering-ECU

(Refer to

P.37-102

). Then go to Step 4.

NO :

The malfunction is intermittent. Refer to
GROUP 00, How to Use
Troubleshooting/Inspection Service Points

−

How to Cope with Intermittent Malfunction

P.00-13

.

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TROUBLESHOOTING

POWER STEERING

37-70

STEP 4. Check whether the diagnosis code is
reset

AC206895

AC

Diagnosis

connector

MB991827

MB991824

MB991910

CAUTION

Before connecting or disconnecting the
M.U.T.-III, turn the ignition switch to the "LOCK"
(OFF) position.
Check again if the diagnosis code is set.
(1) Turn the ignition switch to the "ON" position.

(2) Erase the diagnosis code.
(3) Turn the ignition switch to the "LOCK" (OFF)

position.

(4) Turn the ignition switch to the "ON" position.
(5) Recheck whether diagnosis code U1122 is set.
(6) Turn the ignition switch to the "LOCK" (OFF)

position.

(7) Disconnect M.U.T.-III.

Q: Is the diagnosis code set?

YES :

Replace the hydraulic unit (Refer to

GROUP 35B, Hydraulic Unit

P.35B-78

).

NO :

This diagnosis is complete.

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