1991 MITSUBISHI ECLIPSE sensor

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

5-26BRAKES - 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.

5-36BRAKES - Anti-lock Braking System Troubleshooting
E-3Abnormality of G sensor circuit
[Explanation]The ABS ECU turns on the warning light in the
following cases.
lOFF trouble turning G sensor OFF (It is judged
that the
G sensor continues to be OFF for more
than approximately 13 seconds except when the
lWhen there is a broken wire or short circuit in
the harness for the
G sensor system.
PlUN; F;SIBLEIGNITIONSWITCH (IG2)J/B
G-SENSOR
E-lABSECU
14AO609
Is G sensor normal? (ReferNoto
P.5-86.)Replace G sensor.
I YesWith the ignition key “ON”
_ No m The harness between the
does the voltage betweenG sensor and the ABS
terminal No.6 and groundECU is broken.
indicate battery voltage?
IG sensor circuit is normal.I

5-42BRAKES - Service Adjustment Procedures
BRAKE FLUID LEVEL SENSOR CHECKNO5FBAB(1) Connect a circuit tester to the brake fluid level sensor.
4(2) Move the float from top to bottom and check for
.-,’continuity.
(3) The brake fluid level sensor is in good condition if there is
no continuity when the float surface is above “A”, and if
there is continuity when the float
surface is below “A”.
PARKING BRAKE LEVER STROKE CHECK NWFEAJ
1.Pull the parking brake lever with a force of approx. 200 N(45
Ibs.), and count the number of notches.
Caution
The 200 N (45 Ibs.) force of the parking brake lever must
be strictly observed.
Standard value: 5-7 notches
2.If the parking brake lever stroke is not the standard value,
adjust as described below.
(1) Remove the carpet in the floor console.
(2) Loosen the adjusting nut to the end of the cable rod,
fithus freeing the parking brake cable.
(3) With the engine idling, firmly depress the brake pedal
five or six times and confirm that the pedal stroke stops
changing.
NOTEIf the pedal stroke stops changing, it indicates that the
automatic adjusting mechanism has functioned proper-ly to adjust the clearance between the pads and the
disc to the correct value.
(4) Check to be sure that the clearance between the
stopper and the parking brake lever at the caliper side isas shown in the figure.
NOTEIf the clearance between the parking brake lever and
the stopper exceeds 2 mm
(078 in.), the probable
causes are brake cable sticking, improper wiring, or a
malfunction of the automatic adjuster (within the rear
brake caliper), so it is necessary to check the parking
-brake cable and to disassemble and check the rear
-brake caliper.
(5) Turn the adjusting nut to adjust the parking brake lever
stroke to within the standard value range.

BRAKES - Service Adjustment Procedures5-51E.C.U. terminal
ILow gear idle condition
[Speed: 5-6 km (3.1-3.16
mph)]Approx.
5V
14A0580When increasing speed
[Speed:
15-20 km (9.3-12.4 mph11OBSERVATION OF WHEEL SPEED SENSOR
OUTPUT VOLTAGE VARIATIONS ABS>N65FOAO
(1) Jack up the vehicle and release the parking brake.
(2) Disconnect the electronic control unit harness connector,
and measure the speed sensor output voltage at the
vehicle side harness connector.
(3) With an AWD model, put the shift lever in
1st (MTT) or L(A/T) position, rotate the wheels and observe the wave
shape for each wheel. With an FWD model, put the shift
lever in
1st (M/T) or L (AiT) position, rotate the wheels and
observe the wave shape for the front wheels; for the rear
wheels, rotate the wheels by hand and monitor the wave
shape.
NOTEIt is also
allright to actually drive the car.
ISpeed sensor
E.C.U. terminal No.I
IFront leftI14-15I
IFront right31-33I
IRear right28-30I
IRear left1 10-11IWhen wheel speed is slow, the output voltage is low
and it gets higher as the speed increases.
Wave shape monitoring points
IS THE OUTPUTVOLTAGE (AMPLITUDE) TOO LOW OR ISTHERE NO OUTPUT VOLTAGE?
If it is too low, check each wheel speed sensor,
With FWD rear wheels, check the sensor gap.
IS THERE VARIATION IN THE WAVE SHAPE AMPLITUDE?
If the flicker of the amplitude is large, consider shaking
of the axle hub.
IS THERE NOISE IN THE WAVE SHAPE OR DISTORTION?Broken or disconnected wire due to vibration or
installation malfunction of the wheel speed sensor.
Check rotor teeth meshing, breaks, etc.
Approx. 1 OV
14A0501