Mitsubishi Eclipse / Eclipse Spyder (2000-2002). Service and repair manual — part 578

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-3

System Check Sound
When starting the engine, a thudding sound can
sometimes be heard coming from the engine
compartment. This is a normal sound during the ABS
self-check.

ABS Operation Sounds and Sensations
During normal operation, the ABS makes several
sounds that may seem unusual at first:

•

A whining sound is caused by the ABS hydraulic
unit motor.

•

When pressure is applied to the brake pedal, the
pulsation of the pedal causes a scraping sound.

•

When the brakes are applied firmly, the ABS
operates, rapidly applying and releasing the
brakes many times per second. This repeated
application and release of braking forces can
cause the suspension to make a thumping sound
and the tires to squeak.

Long Stopping Distances on Loose Road
Surfaces
When braking on loose surfaces like snow-covered
or gravel roads, the stopping distance can be longer
for an ABS-equipped vehicle than the stopping
distance for a vehicle with a conventional brake
system.

Shock at starting check
Shock may be felt when the brake pedal is lightly
pressed while driving at a low speed. This is a
normal characteristic because the ABS system
operation check is carried out when vehicle speed is
8 km/h (5 mph) or less.

AN TI-SK ID BR AK IN G SYSTEM (A B S) D IA G N O SIS

INTRODUCTION TO ANTI-LOCK BRAKE SYSTEM DIAGNOSIS

M1352012500084

The anti-lock brake system (ABS) operates
differently from conventional brake systems. These
differences include sounds, sensations, and vehicle
performance that owners and service technicians
who are not familiar with ABS may not be used to.
Some operational characteristics may seem to be
malfunctions, but they are simply signs of normal
ABS operation. When diagnosing the ABS system,
keep these operational characteristics in mind.
Inform the owner of the kind of performance
characteristics to expect from an ABS-equipped
vehicle.

ABS Diagnostic Trouble Code Detection
Conditions

ABS diagnostic trouble codes (ABS DTCs) are set
under different conditions, depending on the
malfunction detected. Most ABS DTCs will only be
set during vehicle operation. Some ABS DTCs will
also be set during the ABS self-check immediately
after the engine is started.
When you check if an ABS DTC will be displayed
again after the DTC has been erased, you should
duplicate the ABS DTC set conditions. Depending on
the detection timing and set conditions for the
specific ABS DTC, you must either drive the vehicle
or turn the engine off and restart it. To set the proper
conditions for that DTC again, refer to "ABS DTC
SET CONDITIONS" for each ABS DTC that you are
trying to reset.

ABS DIAGNOSTIC TROUBLESHOOTING STRATEGY

M1352011100072

Use these steps to plan your diagnostic strategy. If
you follow them carefully, you will be sure that you
have exhausted most of the possible ways to find an
ABS fault.
1. Gather information about the problem from the

customer.

2. Verify that the condition described by the

customer exists.

3. Check the vehicle for any ABS DTC.

4. If you cannot verify the condition and there are no

ABS DTCs, the malfunction is intermittent. Refer
to GROUP 00, How to use Troubleshooting/
Inspection Service Points

−

How to Cope with

Intermittent Malfunctions

P.00-6

.

5. If you can verify the condition but there are no

ABS DTCs, or the system cannot communicate
with the scan tool, check that the basic brake
system is operating properly.

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

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ANTI-LOCK BRAKING SYSTEM (ABS)

35B-4

•

If the basic brake system is not operating
properly, refer to the GROUP 35A, Basic Brake
System Diagnosis

P.35A-5

.

•

If the basic brake system is operating properly,
refer to

P.35B-25

.

6. If there is an ABS DTC, record the number of the

DTC, then erase the DTC from the memory using
the scan tool.

7. Recreate the ABS DTC set conditions to see if the

same ABS DTC will set again.

•

If the same ABS DTC sets again, perform the
diagnostic procedures for the DTC. Refer to

P.35B-8

.

•

If you cannot get the same ABS DTC to set
again, the malfunction is intermittent. Refer to
GROUP 00, How to use Troubleshooting/
Inspection Service Points

−

How to Cope with

Intermittent Malfunctions

P.00-6

.

ABS TROUBLE CODE DIAGNOSIS

M1352011200080

Retrieving ABS Diagnostic Trouble Codes

Using Scan Tool MB991502

Required Special Tool:

•

MB991502: Scan Tool (MUT-II)

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOOK" (OFF) position before
connecting or disconnecting the scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.

2. Turn the ignition switch to the "ON" position.

3. Use scan tool MB991502 to check for ABS diagnostic

trouble codes.

4. Turn the ignition switch to the "LOOK" (OFF) position.

5. Disconnect scan tool MB991502.

Using the ABS Warning Light and Special Tool MB991529

Required Special Tool:

•

MB991529: Diagnostic Trouble Code Check Harness

1. Use special tool MB991529 to ground number 1 terminal of

the data link connector.

CAUTION

Do not depress the brake pedal after the ignition switch is
turned "ON". If the brake pedal is depressed while the ABS
is inoperative and the ignition switch is "ON", the ABS
warning light will remain on. Because of this, diagnostic
trouble codes will not be read out.
2. Turn the ignition switch to the "ON" position.

AC001252AF

16 PIN

MB991502

AC002241AB

MB991529

DATA LINK
CONNECTOR

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

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ANTI-LOCK BRAKING SYSTEM (ABS)

35B-5

3. Read out a diagnostic trouble code by observing how the

warning light flashes.

4. Disconnect special tool MB991529.

Erasing ABS Diagnostic Trouble Codes

Using Scan Tool MB991502

Required Special Tool:

•

MB991502: Scan Tool (MUT-II)

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOOK" (OFF) position before
connecting or disconnecting the scan tool.
1. Connect scan tool MB991502 to the data link connector.

2. Turn the ignition switch to the "ON" position.

3. Use scan tool MB991502 to erase ABS diagnostic trouble

codes.

4. Turn the ignition switch to the "LOOK" (OFF) position.

5. Disconnect scan tool MB991502.

By Special Operation for Brake Pedal

Required Special Tool:

•

MB991529: Diagnostic Trouble Code Check Harness

AC004361AB

ABS WARNING LIGHT

WHEN THE DIAGNOSTIC TROUBLE CODE NO. 24
IS OUTPUT

WHEN NO DIAGNOSTIC TROUBLE CODE IS OUT-
PUT

ACX01777

ILLUMINATED

SWITCHED
OFF

PAUSE
TIME 3s

TENS
SIGNAL

PLACE
DIVISION
2s

UNITS
SIGNAL

1.5s

0.5s

0.5s

AB

ACX01778

ILLUMINATED

SWITCHED
OFF

0.25s

AB

AC001252AF

16 PIN

MB991502

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

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ANTI-LOCK BRAKING SYSTEM (ABS)

35B-6

1. Use special tool MB991529 to ground number 1 terminal of

the data link connector.

NOTE: If the ABS-ECU functions have stopped due to the
fail-safe function, the diagnostic trouble code cannot be
erased.

2. Depress the brake pedal and hold it.

3. Turn the ignition switch to the "ON" position.

4. After turning the ignition switch to the "ON", release the

pedal within three seconds. Repeat this process of pressing
and releasing the brake pedal 10 continuous times.

5. Turn the ignition switch to the "LOOK" (OFF) position.

6. Disconnect special tool MB991529.

AC002241AB

MB991529

DATA LINK
CONNECTOR

AC000937

IGNITION SWITCH

ON

OFF

STOPLIGHT SWITCH

ON

OFF

ABS WARNING LIGHT

ON

OFF

DIAGNOSTIC TROUBLE
CODE MEMORY

3 s

WITHIN
3 s

WITH-
IN 1 s

WITH-
IN 1 s

WITH-
IN 1 s

WITH-
IN 1 s

WITH-
IN 1 s

WITH-
IN 1 s

WITH-
IN 1 s

WITH-
IN 1 s

WITH-
IN 1 s

WITH-
IN 1 s

1 s

1 s

ERASING
COMPLETED

AB

1ST

2ND

3RD

4TH

5TH

6TH

7TH

8TH

9TH

10TH