wheel MITSUBISHI ECLIPSE 1991 Workshop Manual

BRAKES - Anti-lock Braking System Troubleshooting5-14
./
No.Trouble conditionMajor causesRemedyAfter the ignition key is turned to the
l Break in harness for ECU warningCheck, usinflow
“ON” position, it blinks once and then
light drive circuit
chart D. (Re er to9illuminates when it is turned to the
l Malfunction of ECUP.5-18.)“START” position. When the key is
4returned to the “ON” position, the light
blinks again. (Blinking with the ignition
key in the “ON” position is synchronized
with operation noise of the valve relay.)
ABSwarninglighto:-
Ignition
keyACC. LCi+-
14*0593CONTINUED FROM PREVIOUS PAGE
Does the ABS warning light illuminate
when starting to drive the car?
Yes~ Trouble with the motor re-lay, solenoid valve [due toL Check, following trouble
source check charts E-l -self test when driving above
E-6.6 km/h (4 mph)] or malfunc-
NoIs there one-sided braking, insufficient
braking force or malfunction of ABS
operation?
YesTrouble condition
Major causes
One-sided braking
Insufficient braking forcel Mechanical lock of HU solenoid valve
l Hydraulic line in HU is clogged.
Decline in ABS function
(Wheels easily lock when there is sud-
den braking.)
ABS sometimes functions even when
there is no sudden braking. (ABS opera-
tion vibration is transmitted.)
1 tion of wheel speed sensor 1
NoNormall Malfunction in HU solenoid valve op-
erationl Hydraulic line in HU is clogged.
l Insufficient wheel speed sensor out-
put voltage (sensor malfunction, too
large a gap between sensor rotor,
missing rotor teeth or temporarily
broken wire in sensor harness)
l Malfunction of ABS ECU
RemedyCheck HU operation and, if
necessary, replace HU.
If HU is normal, check
structural parts for normal
braking. (Refer to
P.5-7.)Check wheel speed sensor
(Refer to
P.5-82.) and, ifnecessary,replace sensor,
adjust gap or replace rotor.
If tests indicate that there are
no mechanical or electrical
failures, replace the ECU.

BRAKES - Anti-lock Braking System Troubleshooting549
E-lInput abnormality of wheel speed sensorI-[Explanation][Hint]The ABS ECU detects breaks in the wheel speed
In addition to a broken wire/short circuit in the wheelsensor wire. The warning light lights up if the wheel
speed sensor, also check whether the sensor gap isspeed sensor signal is not input (or short circuited)
too large, rotor teeth are missing, sensor harness
or if its output is low when starting to drive or while
wire is temporarily broken, or sensor harness and
driving.body connector are not properly inserted.
I IE-2Output abnormality of wheel speed sensorI
[Explanation]The warning light lights up when there is an
abnormality (other than broken wire or short circuit)
in the wheel speed sensor output signal while
driving.
[Hint]
The following can be considered as the cause of thewheel speed sensor output abnormality.
l Distortion of rotor, teeth missing
lLow frequency noise interference when sensor
harness wire is broken
l Noise interference in sensor signall When the sensor output signal is below the
standard value or when amplitude modulation is
over the standard value, using an oscilloscope tomeasure the wave shape of the wheel speed
sensor output signal is very effective.
l Loose wheel bearing
l Temporarily broken wire in sensor harness
l Sensor harness and body connector are not
properly inserted.
NOTE
If contact is poor, check the sensor cable by bendingand lightly stretching it.
SPEED SENSOR
FRONTREAR(LEFT SIDE) (RIGHT SIDE) (LEFT SIDE) (RIGHT SIDE)
Km
I-.IIGND
III24I
FRONT SIDE
I
ABSECU
REVERSE SIDE
SELF-DIAGNOSIS
CHECK CONNECTOR
14AO601

5-20 _BRAKES - Anti-lock Braking System TroubleshootingCheck flow connected with wheel speed
sensorNOTE:When checking with an oscilloscope, first measure voltage
variations in the wheel speed sensor output. (Refer to
P.5-51.)
Is the resistance value of the wheelNo c Malfunction of wheel speedReplace wheel speed
speed sensor part, which the displayedsensor
sensor.trouble code indicates, normal?
Standard value:
0.8-l .2 kQ
I YesIs the resistance value with the ECU
No c Harness wire for wheel -Repair harness.connector normal?
speed
sensorcircuit is
Ibroken.
II1
1
Is the standard value for the
gap between the wheel
speed sensor and rotor,
which the output trouble
code indicates, within the
range?
Standard value:
h
%Z~Pf!;!~~~e~no missing or damaged
teeth?
1 Yes
1Check the output of each
wheel speed sensor with an
oscilloscope, including the
waveform. (Refer to
measurement ofwheel
speed sensor output voltage
variations on
P.5-51 .I Is the
output voltage for each
wheel speed sensor over
the standard value and is thewave form normal?
Yes
Canthe abnormality beNoRepair harness.foundeven if the sensorIharness and connection be-
tween sensor harness and
body harness are bent and
estretched?
Yes

5-24BRAKES - Anti-lock Braking System Troubleshooting
E-6 Abnormality of motor drive circuit
[Explanation]The ABS ECU illuminates the warning light for the
motor relay and motor in the following cases.
l When the motor relay does not function
lWhen there is trouble with the motor itself and it
does not revolve
lWhen the motor ground line is disconnected and
[Hint]If there is motor operation noise when wheel speed
exceeds
Gkm/h (4mph) when starting up after the
engine is started, there is a broken or short circuitedmotor monitor wire.
the motor does not revolve
l When the motor continues to revolve
14A0605Does the motor make a
YesBroken wire or short cir-noise when wheel speedcuit in motor monitor line
exceeds 6 km/h (4 mph)?
1Repair the harness be-
tween HU and ECU.
, NoRemove the motor relay.
Remove the motor relay andcheck resistance values.
No. 85-No. 86:resistancevalue
30-60 52No.30-No.87: no continui-
ty
Battery voltage is applied onterminals No. 86 and No.85
grounded.No.30-No.87: continuity
IYesIs pump motor ground con-
NoConnect ground wire.
netted normally?
IlYes
motor relay and re-
move HU connector.>Does voltage between body
connector terminal 51 and
No c Broken wire in pump
motor power circuit
ground indicate battery vol-
tage?4Repair the harness.
YesIs resistance between body
NoMalfunction of harnessconnector terminal No. 2 andbetween HU and ECUNo.26 30-60 ohms?iII1Repair harness.

5-26BRAKES - Anti-lock Braking System Troubleshooting
No.Trouble conditionMajor causesRemedyAfter the ignition key is turned to the
l Break in harness for ECU warningCheck, using flow“ON” position, it blinks once and thenlight drive circuitchart D. (Refer to P.5-illuminates when it is turned to the
l Malfunction of ECU33.)“START” position. When the key is
returned to the “ON” position, the light
4blinks again. (Blinking with the ignition
key in the “ON” position is synchronized
with operation noise of the valve relay.)
ABSwarning
light
0:~
Ignition
keyACC. iv-
14A0593CONTINUED FROM
PREVIOU? PAGE
I ,
Does the ABS warning light illuminateYes* Check, following trouble
when starting to drive the car?L Trouble with the motor re-lay, solenoid valve [due to
self test when driving above
6 km/h (4 mph)] or malfunc-source check charts E-l -E-7.
Notion of wheel speed sensor
Normal
YesTrouble condition
Major causes
RemedyOne-sided brakingl Mechanical lock of HU solenoid valveCheck HU operation and, if
Insufficient braking forcel Hydraulic line in HU is clogged.
necessary, replace HU.
If HU is normal, check
Decline in ABS functionl Malfunction in HU solenoid valve op- structural parts for normal
(Wheels easily lock when there is
sud-
erationbraking. (Refer to P.5-2.)den braking.)l Hydraulic line in HU is clogged.
ABS sometimes functions even whenl Insufficient wheel speed sensor
out-Check wheel speed sensor
there is no sudden braking. (ABS opera-put voltage (sensor malfunction, too (Refer to P.5-82.) and, if
tion vibration is transmitted.)
large a gap between sensor rotor, necessary, replace sensor,
missing rotor teeth or temporarily adjust gap or replace rotor.
broken wire in sensor harness)
If tests indicate that there are
l Malfunction of ABS ECU
no mechanical or electrical
failures, replace the ECU.

5-34BRAKES -Anti-lock Braking System Troubleshooting
E-lInput abnormality of wheel speed sensorI.
[Explanation][Hint]s”rThe ABS ECU detects breaks in the wheel speed
In addition to a broken wire/short circuit in the wheel--sensor wire. The warning light lights up if the wheel
speed sensor, also check whether the sensor gap isspeed sensor signal RL is not input (or shorttoo large, rotor teeth are missing, sensor- harness
circuited) or if its output is low when starting to drivewire is temporarily broken, or sensor harness and
or while driving.body connector are not properly inserted.
E-2Output abnormality of wheel speed sensor
[Explanation]The warning light lights up when there is an
abnormality (other than broken wire or short circuit)
in the wheel speed sensor output signal while
driving.
[Hinti
The following can be considered as the cause of thewheel speed sensor output abnormality.
l Distortion of rotor, teeth missing
lLow frequency noise interference when sensor
harness wire is broken
l Noise interference
in sensor signall When the sensor output signal is below the
standard value or when amplitude modulation is
over the standard value, using an oscilloscope tomeasure the wave shape of the wheel speed
sensor output signal is very effective.
l Loose wheel bearing
l Temporarily broken wire in sensor harness
l Sensor harness and body connector are not
properly inserted.
NOTE
If contact is poor, check the sensor cable by bendingand lightly stretching it.
SPEED SENSOR
FRONTREARP%(LEFT SIDE)
(RIGHT SIDE)(LEFT SIDE)(RIGHT SIDE),’
1
FRONT SIDE
SELF-DIAGNOSISCHECK CONNECTOR14AO608

BRAKES - Anti-lock Braking System Troubleshooting5-35Check flow connected with wheel speed
NOTE:
sensorWhen checking with an oscilloscope, first measure voltagefl-variations in the wheel speed sensor output. (Refer to P.5-51.)Is the resistance value of the wheel
speed sensor part, which the displayed
No cMalfunction of wheel speed _~ Replacewheel speedsensor
sensor.trouble code indicates, normal?
Standard value:
0.8-l .2 kQIs the resistance value with the ECU
No* Harness
wireforwheelRepair harness.connector normal?
speedI
broken.Is the standard value tor the
gap between the wheel
speed sensor and rotor,
which the output trouble
code indicates, within the
range?Standard value:
h;ti;j3-0.9 mm (.012-Rear
Nb adjustment
- No
the wheel speed sensor. Replace rotor that has
rotor that the trouble code
missingor damaged
indicates, normal and withteeth.
missing or damaged
Check the output of each
wheel speed sensor with an
oscilloscope, including the
wave form.
(Refewhekqmeasurement of
speed sensor output voltage
variations on
P.5-51.) Is the
output voltage for each
wheel speed sensor over
the standard value and is thewave form normal?I
YesCan the abnormality be
found even if the sensor
harness and connection be-
tween sensor harness and
body harness are bent and
stretched?
No
Repair harness.

5-40BRAKES - Anti-lock Braking System Troubleshooting
E-7Abnormality of motor drive circuit
[Explanation]The ABS ECU illuminates the warning light for the
motor relay and motor in the following cases.
l When the motor relay does not function
lWhen there is trouble with the motor itself and it
does not revolve
[Hint]If there is motor operation noise when wheel speed
exceeds
Gkm/h (4mph) when starting up after the
engine is started, there is a broken or short circuitedmotor monitor wire.
lWhen the motor ground line is disconnected andthe motor does not revolve
l When the motor continues to revolve
Does the motor make a
YesBroken wire or short cir-noise when wheel speed
-cuit in motor monitor line
exceeds 6 km/h (4 mph)?
b
NoRepair the harness between HU and ECU.
emove the motor rela
ABS ECU
14A0105
Remove the motor relav and
check resistance values.
No.
85-No. 86:resistancevalue 30-60 QNo.30-No.87: no continui-
ty
Battery voltage is applied on
terminals No. 86 and No. 85
grounded
No. 30-No. 87: continuity
Yes
q Motor relay malfunction 1
Replace motor relay.I
Is pump motor ground con-netted normally?Connect ground wire.I
b
Does voltage between bodyNo
connector terminal 51 andIBroken wire in pumpmotor power circuit
ground indicate battery vol-
tage?1Repair the harness.
YesIs resistance between body
- No L Malfunction of harness
connector terminal No. 2 andbetween HU and ECU
No.26 30-60 ohms?b
YesRepair harness.
Motor drive circuit is normal.

BRAKES - Service Adjustment Procedures5-43When engine is
stoppedNo good
0
wtwo061
VV;Videngine is
t4uoo60
Caution
If the number of brake lever notches engaged is less
than the standard value, the cable has been pulledexcessively, and failure of the automatic adjuster
mechanism will result. Be sure tti adjust it to within the
standard value.(6) After making the adjustment, check to be sure that there is
no play between the adjusting nut and the pin. Also check
to be sure that the adjusting nut is securely held at the nut
holder.(7) After adjusting the lever stroke, jack up the rear of the
vehicle.(8) With the parking brake lever in the released position, turn
the rear wheel to confirm that the rear brakes are not
dragging.
PARKING BRAKE SWITCH CHECKN05FDAB
(1) Disconnect the connector of the parking brake switch, and
connect an ohmmeter to the parking brake switch and the
switch installation bolt.
(2) The parking brake switch is good if there is continuity whenthe parking brake lever is pulled and there is no continuity
when it is returned.
BRAKE BOOSTER OPERATING
lNSPECTIONNoSFcuFor simple checking of brake booster operation, carry out the
following tests.
(1) Run the engine for one or two minutes, and then stop it.
(2) Step on the brake pedal several times with normal
pressure.If the pedal depressed fully the first time. but gradually
becomes higher when depressed succeeding times, the
booster is operating properly.
If the pedal height remains unchanged, the booster is
faulty.(3) With the engine stopped, step on the brake pedal several
times with the same pressure to make sure that the pedal
height will not change.
Then step on the brake pedal and start the engine.
If the pedal moves downward slightly, the booster is in
good condition. If there is no change, the booster is faulty.
(4) With the engine running, step on the brake pedal and then
stop the engine.
Hold the pedal depressed for 30 seconds. If the pedal
height does not change, the booster is in good condition.
If the pedal rises, the booster is faulty.
If the above three tests are okay, the booster performance canbe determined as good.
If one of the above three tests is not okay at last, the check
valve, vacuum hose, or booster will be faulty.

BRAKES - Service Adiustment Procedures5-45I
\\14A0416
2314A04.54
BLEEDINGN65FYAN
When the master cylinder is empty of brake fluid, bleed air
from the master cylinder by proceeding with procedures (1)
thru (6). (Because this master cylinder is not equipped with a
check valve.)
When brake fluid remains in the master cylinder, proceed with
step (6).
(1) -Disconnect the brake tube from the master cylinder.
(2) Two persons should conduct the air bleeding, one person
slowly depressing the brake pedal and holding the pedal
depressed.(3) In this condition, the other person should use a finger to
close the outlet part of the master cylinder, and then the
first person should release the brake pedal.
(4) Steps (2) and (3) should be repeated three or four times,
and then the master cylinder should be filled with brake
fluid to the specified level.
NOTE
The air is completely bled from the master cylinder by steps
(1) to (4).
(5) Connect the brake tube to the master cylinder.
(6) Start the engine; then, in the sequence shown in the
illustration, bleed the air from each wheel cylinder.
Specified brake fluid: MOPAR Brake Fluid/
Conforming to DOT3
Caution
1.Use the specified brake fluid. Avoid using a mixture
of the specified brake fluid and other fluid.2. If brake fluid is exposed to the air, it will absorb
moisture; as water is absorbed from the atmos-phere, the boiling point of the brake fluid will
decrease and the braking performance will be
seriously impaired. For this reason, use a hermeti-
cally sealed 1 lit.
(1.06 qt.) or 0.5 lit. (0.52 qt.) brake
fluid container.3. Firmly close the cap of the brake fluid container
after use.
4. For vehicles with the anti-lock braking system, besure to install a filter to the master cylinder
reservoir tank when supplying brake fluid.
ORDINARY AIR-BLEEDING PROCEDURES(1) Depress the brake pedal several times until resistance is
felt; then, with the pedal depressed, loosen the bleeder
screw
l/3 to l/2 turn and then tighten it before the fluid
pressure is all gone.
(2) Release the brake pedal. Repeat this procedure until there
are no more air bubbles in the brake fluid.