Mitsubishi Grandis. Manual — part 914

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-71

DIAGNOSIS

STEP 1. MUT-III CAN bus diagnostics

Use MUT-III to diagnose the CAN bus lines.

CAUTION

Before connecting or disconnecting the MUT-III,
turn the ignition switch to the "LOCK" (OFF)
position.
(1) Connect MUT-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 lines. (Refer to GROUP
54D, Diagnosis-Can Bus Diagnostic Chart

P.54D-16

). Then go to Step 4.

STEP 2. MUT-III diagnosis code

CAUTION

Before connecting or disconnecting the MUT-III,
turn the ignition switch to the "LOCK" (OFF)
position.
(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 if the diagnosis code is set.
(6) Turn the ignition switch to the "LOCK" (OFF)

position.

Q: Is any diagnosis code set?

YES :

Refer to

P.35B-7

, Diagnosis Code Chart.

Then go to Step 4 .

NO :

Go to Step 3.

AC302297

AC310120

AB

MB991827

16-pin

MB991910

MB991824

AC302297

AC310120

AB

MB991827

16-pin

MB991910

MB991824

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-72

STEP 3. MUT-III other system diagnosis code

CAUTION

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

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Check for Combination meter system diagnosis

code.

(4) Turn the ignition switch to the "LOCK" (OFF)

position.

(5) Disconnect MUT-III.

Q: Is code No.U1102 set?

YES :

Replace the hydraulic unit (integrated with

TCL/ASC-ECU). Then go to Step 4.

NO :

Replace the combination meter assembly.
(Refer to GROUP 54A, Combination Meter
Assembly

P.54A-84

). Then go to Step 4.

STEP 4. Retest the system

Q: Turn the ignition switch to the "ON" position. Do

the ABS warning lamp illuminate for three
seconds, and then go out after the engine starts?

YES :

The procedure is complete.

NO :

Return to Step 1.

INSPECTION PROCEDURE 5: ABS System dose not Operate.

COMMENT

The fail-safe function is probably canceling ABS
system. In this case, MUT-III can be used to Retest
each system by checking the diagnosis codes.

PROBABLE CAUSES

• Malfunction of the CAN bus line.

• Malfunction of the ABS-ECU.

DIAGNOSIS

STEP 1. Hydraulic unit check

Refer to

P.35B-75

.

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Connect the brake pipes correctly, repair the
external brake lines, or replace the hydraulic
unit.

STEP 2. Verify that the condition described by
the customer exists.

Q: Can any faults be found with the brake operation?

YES :

Check the brake system related

components except the ABS system.

NO :

The procedure is complete.

DATA LIST REFERENCE TABLE

M1352011500724

The following items can be read by the MUT-III from
the ABS-ECU input data.

AC302297

AC310120

AB

MB991827

16-pin

MB991910

MB991824

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-73

When the system is normal.

When the ABS-ECU shut off ABS operation.

When the diagnosis system stops the ABS-ECU, the
MUT-III display data will be unreliable.

ACTUATOR TEST REFERENCE TABLE

M1352011600721

The MUT-III activates the following actuators for
testing.
NOTE: If the ABS-ECU runs down, actuator testing
cannot be carried out.
NOTE: Actuator testing is only possible when the
vehicle is stationary.
NOTE: The ABS warning lamp continues illuminating
until the communication between MUT-III and
ABS-ECU is completed.

ACTUATOR TEST SPECIFICATIONS

CHECK AT ABS-ECU

M1352011800703

Use the following steps to remove the connector
cover and measure the terminal voltage.

1. Move the lock lever of the ABS-ECU connector as

shown in the illustration, and then disconnect the
ABS-ECU connector.

Item
No.

Check item

Checking requirements

Normal valve

01

Front-right wheel speed sensor

Perform a test run

Vehicle speeds
displayed on the
speedometer and
MUT-III are
identical.

02

Front-left wheel speed sensor

03

Rear-right wheel speed sensor

04

Rear-left wheel speed sensor

05

ABS-ECU power supply voltage

Ignition switch: ON

10

− 16 V

06

Stop lamp switch

Depress the brake pedal.

ON

Release the brake pedal.

OFF

AC100172 AG

Activation pattern

A

B

C

Solenoid
valve

End of
activation

Start of
activation

1 s

2 s

Pump
motor

ON

OFF

NOTE
A:
B:
C:

Hydraulic pressure increases
Hydraulic pressure holds
Hydraulic pressure decreases

0.01 s

0.05 s

No. Item
01

Solenoid valve for
front-right wheel

Solenoid valves
and pump motors
in the hydraulic
unit (simple
inspection mode)

02

Solenoid valve for
front-left wheel

03

Solenoid valve for
rear-right wheel

04

Solenoid valve for
rear-left wheel

AC311278AB

Oil reservoir

Lock lever

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-74

2. Connect special tool ABS check harness

(MB991974) to measure the voltages between
each check connector terminals and earth
terminals 13 or 26.

TERMINAL VOLTAGE CHECK CHART

1. Measure the voltages between earth terminal (13)

or (26) and each respective terminal.

2. The terminal layouts are shown in the illustrations

below.

NOTE: Do not measure terminal voltage for
approximately three seconds after the ignition switch
is turned to the "ON" position. The ABS-ECU
performs the initial check during that period.

AC303576

MB991974

ABS-ECU

AD

ABS-ECU
harness
connector

1

3

4

5

6

7

8

9

10

11

2

13 12

16

17

18

19

20

21

22

23

24

15

25

14

26

Check connector

AC313002

Terminal
No.

Check item

Checking requirements

Normal condition

1

Solenoid valve power supply

Ignition switch: "ON"

System voltage

3

Wheel speed sensor (RL) power
supply

Ignition switch: "ON"

System voltage

5

Wheel speed sensor (FR) power
supply

Ignition switch: "ON"

System voltage

9

Wheel speed sensor (FL) power
supply

Ignition switch: "ON"

System voltage

11

Wheel speed sensor (RR) power
supply

Ignition switch: "ON"

System voltage

14

Motor power supply

Ignition switch: "ON"

System voltage

16

Stop lamp switch input

Stop lamp switch: "ON"

System voltage

Stop lamp switch: "OFF"

Approximately 0 V

20

ABS-ECU power supply

Ignition switch: "ON"

System voltage

Ignition switch: "START"

Approximately 0 V