1990 MITSUBISHI SPYDER service

ABS Troubleshooting
INSPECTION PROCEDURE CLASSIFIED BY DIAGNOSTIC TROUB LE
Code No. Wheel speed sensor open circuitProbable
[Comment]The ABS-ECU detects breaks in the wheel speed sensor wire.l
Malfunction of wheel l Malfunction of wiring harness or l Malfunction of ABS-ECU
NG Repair(Refer to
OK
Measure at ABS-ECU connector l Disconnect the connector and mea-
sure at the harness side.
l Resistance value between terminals
NG Check the following connectors: NG Repair landI
Wheel speed sensor output voltage check
O K
Wheel bearing end play check Refer to GROUP 26
On-vehicleService.Refer to GROUP 27 On-vehicleService.
Check the following connector:
l
OK1Check trouble symptom.
NG Repair
Replace the ABS-ECU.
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ABS
Code No. 38 Stop light switch system
[Comment]
The ABS-ECU outputs this diagnostic trouble code in the following cases.l Malfunction of stop light switch Malfunction of or lStop light switch remains on for more than 15 minutes while the ABS is . M a l f u n c t i o n ing.l The harness wire for the stop light switch may be o pen-circuited.If the stop light operates normally, there is an open circuit in the harness for the
stop light switch input circuit or there is a malfu nction in the ABS-ECU.
Yes
Stop light switch check (Refer to
GROUP On-vehicle Service.) Replace the
Measure at ABS-ECU connector l
Disconnect the connector and mea-
sure at the harness side.
l Stop light switch: ON
lVoltage between terminal 29 and body
ground
OK Battery positive
OK
Check the following connector:
l
OK
Check trouble symptom.
NG Repair
NG Replace the ABS-ECU.
Revision

ABS Troubfeshooting , .
INSPECTION PROCEDURE 7
Break operation is abnormal
[Comment]This varies depending on the driving conditions and the road surface conditions, soproblem diagnosis is difficult. However, if a normal diagnostic trouble code is displayed,carry out the following
l Malfunction of wheel speed l Malfunction of ABS rotor
l Malfunction of wheel bearing
of hydraulic Malfunction of ABS-ECU
NG Repair
(Refer to
Wheel speed sensor output voltage check [ R e p l a c e t h e w h e e l
Hydraulic unit check (Refer to 1NGABS rotor check (Refer to Replace the rotor.
O K NGWheel bearing end play check Refer to GROUP 26 On-vehicle Repair
Service.Refer to GROUP 27 On-vehicleIService.I
Check trouble symptom.
ABS-ECU connector l Disconnect the connector and
measure at the harness side.
l Resistance vaiue between termi-
nals
14-15, and
O KThe sensor harness and connector
should be moved while these checks
are carded out.
OK
Repair
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Repair
.
NG Repair
OK
Check trouble symptom.N G Replace ABS-ECU.

On-vehicle. Service
Check connector
l
harness
ON-VEHICLE SERVICE
C a u t i o n
Use the specified brake fluid. Avoid using a mixture of
the specified brake fluid and other fluid.
Specified brake fluid:
or
MASTER CYLINDER BLEEDING
Refer to GROUP
On-vehicle Service.
BRAKE LINE BLEEDING
Refer to GROUP
On-vehicle Service.
Caution
For with ABS, be sure to filter/strain the brake
fluid ‘being added to the master cylinder reservoir tank.
Debris may damage the HU.
OPERATION CHECK35200130101
WHEEL SPEED SENSOR OUTPUT VOLTAGE
1. Lift up the vehicle and the brake.
2. Disconnect the ECU harness connector and measure from the harness side connector.
Caution
Set the special tool and use the check connector to
check. Do not connect the connector “(Special
marked with except when recording the waveform
. on’ a test. I n s u c h
connector to the ECU.
3. Rotate the wheel to be measured at approximately
.;
1 rotation per second, and voltage
using a circuit tester or an
Output voltage.
When measuring with a voltmeter:
or more
When measuring with an oscilloscope:
p-p or more
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Service
Connector terminal arrangement
Terminal arrangement shown on thespecial tool connector
0 0 0 0 0 0 7 6
L - L - -
,
I
When idling (5-6 km/h) gear (manual transaxle) or- I - - -
. - i - - ~ - - - ; - - ; - - - c - - ? - - - c - - : - - - ; - - ~ - - - i range (automatic
,Caution,
1.Use the special tool to
terminal and resistance.
2. The connector for
i s t h e
arrangement shown on the special tool
So take the readings from
the special tool when checking.
Example
c o n n e c t o r Terminal
numberthe-special tool connector
181
If output voltage is lower than the above values, the
reason
be follows:
l Faulty wheel
sensor.
,
,
Inspecting Wave Forms With An Oscilloscope
Use the following method to observe the output volt age wave
form from each wheel sensor with an oscilloscope
l
Start the engine, and rotate the front wheels by en gaging
gear (vehicles with manual transaxle) or range
(vehicles with automatic transaxle). Turn the rear wheels
manually so that they rotate at a constant speed.
NOTE
1. Check the connection of the sensor harness and
connector before using the oscilloscope.
2. The wave form measurements can also be taken whi le
the vehicle is actually moving.
3. The output voltage will be low when the wheel sp eed
is low, and similarly it will be higher as the whee l speed
increases.
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On-vehicle Service .
Points In Waveform Measurement
SymptomProbable causes
Too small or zero waveform
Faulty wheel speed sensor Replace sensor
amplitude
. .
Waveform amplitude fluctuates Axle hub eccentric or with large
cessively (this is no problem if the
Replace
minimum amplitude is 100 or
more)
Noisy or disturbed waveform Open circuit in sensorR e p l a c e s e n s o r
Open circuit in harness Correct harness
Incorrectly mounted wheel speed sensor Mount correctly
rotor with missing or damaged teethReplace ABS rotor
NOTE
The wheel speed sensor cable moves following motion
of the front or rear suspension. Therefore, it is that
it has an open circuit only when driving on rough r oads and it functions normally on ordinary roads.
is, therefore,
recommended to observe sensor output voltage wavefo rm also under conditions, such as rough road driving.
Revision

ABS On-vehicle Service
6.Turn the wheel hand the’change
force when the brake pedal is depressed
When using the braking force tester,
brake
pedal, until the braking force
values,
and check to be sure that the farce changes!
to the brake drag force, step 2 when the,
actuator is force-driven.
Rear wheel
The result should be as shown in the following diag ram.
7.If the result of inspection is abnormal, correct according
to the “Diagnostic Table.”
Depressed
Released
Increase in pressure
Reduction in pressure
(when not working)
Steady pressure
Lock
Drag force when the
pedal is
- - - ! - - - ; - - - t - - - ! - - - : - - - ~ - - - ; - - - : - - - i - - - ~ - -
I
Scan tool actuator test ,
, , (Item Nos. 04, 05) start --C--y----L--
, ,
Diagnosis Table
No.
04
Operation
(1)Depress brake pedal to
lock wheel.
(2) Using the scan tool,
select the wheel to be
checked and force the
actuator to operate.
(3)Turn the selected wheel
manually to check the
change of brake force.
05
Normal
Brake force re-
leased for 6 se-
conds after lock-
ing.
AbnormalProbable cause Remedy
Wheel does not Clogged brake Check and clean
lock when brake line other than brake line
pedalisde- HU
pressed.Clogged hydrau- Replace HU
circuit in HUsembly
Brake force is not IncorrectHU Connect
releasedbrake tube con-
HUsolenoid Replace HU
valve not sembly
tioning correctly
8. After inspection, disconnect the scan tool immed iately
after turning the ignition switch to OFF.
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ABS On-vehicle Service
Screwdriver
MOTOR RELAY AND ABS VALVE RELAY
1. the splash shietd.
( R e f e r t o G R O U P 4 2
2. Remove the relay box
3. the tip of a screwdriver into the
the hydraulic unit and the relay “box and use it
to open the tab at place, and then the cover.’
4.Take out of the relays the box,
the continuity between the terminals power is not
supplied and when power
Motor Relay
When no current Between terminals
flows
Between terminals No continuity
When current flows Between terminals Continuity
between terminals
(approx. 0
ABS Valve Relay
When no current Between terminals 20
flows
Between terminals Continuity
(approx. 0
Between terminals No continuity
When current flows Between terminals No continuity between terminals 30
Between terminals Continuity
(approx. 0
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