1990 MITSUBISHI SPYDER ECU

INSPECTION PROCEDURE CLASSIFIED BY DIAGNOSTIC TROUBLE
Code No. Wheel speed sensor open circuitProbable cause
[Comment]The ABS-ECU detects breaks in the wheel speed senso
r wire. o f w h e e l S p e e d Malfunction of wiring harness l Malfunction of ABS-ECU
,
lDisconnect the connector and mea-
sure at the harness side.
l Resistance value between terminals
a n d O KCheck trouble symptom.each wheel speed sensor and the
Wheel speed sensor check(Refer to GROUP -Wheel Sensor Check.)
Replace the wheel speed sensor.
IOKN GABS rotor check (Refer to Replace the ABS rotor.
Refer to GROUP 26 On-vehicle
Refer to GROUP 27
On-vehicle
Check the
connector: N G
l Repair
OK
1
Check trouble symptom. Replace the ABS-ECU.
1
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,

Code No. 15 Wheel sensor svstem
[Comment] of . This diagnostic trouble code is output when there is an abnormality (other than brokenwire or short circuit) in any of the wheel speed sensor output signals while driving.l
Malfunction of harness
The following can be considered as the cause of the wheel speed sensor outputl
Malfunction of ABS rotor
l
wheel abnormality.l Malfunction of ABS-ECU
l Distortion of ABS rotor, teeth missing
l Low frequency noise interference when sensor harnes s is broken
l Noise interference in sensor signal
,lSensor output signal is below the standard value or amplitude modulation is over
the standard value. Using an oscilloscope to measur e the wave shape of the
wheel speed sensor output signal is very effective.
l Broken sensor harness
Poor connection of connector
I-NGWheel speed sensor insulation check Repair
(Refer to
OK
(Refer to(Refer to GROUP -Wheel Speed
Refer to 28 On-vehicleService.Refer to GROUP 27 On-vehicle wheel speed sensors and the
ABS-ECU. Repair, if necessary.
Check the following connector: l
OK
Check trouble symptom.
NG
the ABS-ECU.
Service.
NG Repair
,
Code No. 21 G-sensor systemProbable cause
[Comment]l Malfunction of G-sensor
The ABS-ECU outputs this diagnostic trouble code in the following cases.
l Malfunction of wiring harness or connector
lWhen there is an open or short circuit in the harne ss for the G-sensor system.
l Malfunction of ABS-ECU
G-sensor check (Refer to
Replace the G-sensor.
Measure at ABS-ECU connector
l Ignition switch ONlVoltage between terminal 8 and bodygroundOK 2.4-2.6 Check the harness between theOKCheck trouble symptom.G-sensor and the ABS-ECU. Repair,
NGif necessary.Check the following connector:
. Repair
OK
Check trouble symptom.
N G
Replace the ABS-ECU.

ABSTroubleshooting.
Code No. 22 Stop switch system
[Comment]The ABS-ECU outputs this diagnostic trouble code in the following cases.Stop light switch remains on for more than 15 minutes while the ABS is not function-ing.l The harness wire for the stop light switch may be o pen.
If the stop light operates normally, there is an op en circuit in the harness for the
stop light switch input circuit is broken or there is a malfunction in the ABS-ECU.
l Malfunction of stop light switch of harness or connector l Malfunction ‘of
,
Does the stop light illuminate and switch
off
Yes
(Refer to GROUPBrake pedal.)
OK
Stop light switch check (Refer to
GROUP On-vehicle Service.)
OK
Replace the light
l Disconnect the connector and mea-
sure at the harness side.
l Stop light switch ON
l
Voltage between terminal 29 and body
ground
OK Battery positive voltage
OK
Check the harness between dedicated
Check the following co l
OK
Repair
Check trouble symptom. Replace the ABS-ECU.
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ABS, . ,
Code No. Solenoid valve system .
[Comment]l Malfunction of hydraulic unitThe ABS-ECU monitors the solenoid valve drive circuit.lIf no current flows in the solenoid even if the ECU turns the solenoid ON or if it of l Malfunction of ABS-ECU
continues to flow even when turned OFF, the ECU det ermines the solenoid coil wire
is broken/short-circuited or the harness is broken/ short-circuited, and then these
diagnostic trouble codes are output.
,
l Disconnect the connector and mea-
sure at the hydraulic unit side.
l Resistance value between terminals
lDisconnect the connector and mea-
l t R e p a i r
sure at the harness side.
l Resistance value between terminals
OK
22-17 and 22-35.
O K Check trouble symptom.
NG
OKNG
.
OK
Repair
Check trouble Replace the ABS-ECU.
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[Comment]l of relayWhen ignition switch is ON, the, switches the valve relay OFFland ON for an check, compares of the signal to the valve relay l of hydraulic unitand valve power monitor line voltage to check wheth er the relay operation is.normal.In addition, normally it monitors whether or not th
ere ISpower in the valvepower monitor line since the valve relay is normall y ON. If. the of powerto the valve power monitor line is interrupted, this diagnostic trouble code be,
..output. ,.
N G
OK
Replace the valve
Measure at unit connector NG
l Disconnect the connector and mea-
sure at the harness side.
lVoltage between terminal 12 and body
Measure at ABS-ECU connector l Disconnect the connector and mea-
sure at the harness side.
l Resistance value between terminals
2
27.
O K
Measure at ABS-ECU connector l Disconnect the connector and mea-
sure at the harness side.
lCountinuity between terminal 22 and
body ground
OK
Countinuitv
N G
N G
Check trouble symptom.
N G
Check the between hy-draulic unit and the ABS-ECU. Repair,if necessary.
OK __
C h e c k t h e c o n n e c t o r : NG Repair
l
OK
Check trouble symptom.NG Replace the ABS-ECU.

ABS , ,
Code No. 52 Motor relay, motor system
[Comment]The ABS-ECU outputs this diagnostic trouble code for the motor relay and motor
in the following cases.
lWhen motor relay is ON and no signal is input to th e motor monitor line (when
motor is not operating, etc.)
l When 5 seconds or more (when motor continues operating, etc.)
l When the motor relav does not function
ABS motor relay check (Refer to
OK Replace the ABS motor relay.
the, harness between fusible
link NO.8 and the hydraulic unit.
Measure at ABS-ECU connector
l Disconnect the connector and
l Resistance value between terminals side.
OK
Measure at ABS-ECU connector l Disconnect the connector and mea-
sure at the harness side.
lResistance value between terminal 5
and body ground
O K
Check trouble
NG
Check the between the hy-
draulic unit and ABS-ECU. Repair, if
NG
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Check the motor ground and repair if
OK
Replace the hydraulic unit.
OKNGCheck the Repair
.
OK
Check trouble symptom. Replace the ABS-ECU.

ABS
Caution
1.If movements are made when driving at speed, or when driving on road
with low frictional resistance, or when passing over bumps, the ABS may
sudden braking is not being applied. of this, when getting
2.
check if the problem occurred while driving under s uch conditions
During ABS operation changes in the feeling of the brake pedal occur or
may not be able to be depressed). Such changes are due to in hydraulic
pressure inside the brake line to prevent, the whee ls from locking,
I N S P E C T I O N P R O C E D U R E F O R T R O U B L E S Y M P T O M S ,
INSPECTION PROCEDURE 1
Communication with scan tool is not possible. Probable cause
(Communication with all systems is not possible.)
[Comment]l Malfunction of connector
The reason is probably a defect in the power supply system (including ground) for
the diagnostic line. l
Malfunction harness
Refer to GROUP Troubleshooting
INSPECTION PROCEDURE 2
Communication with scan tool is not possible.
(Communication with ABS only is not Probable cause
,
[Comment]l Blown fuse
When communication with the scan tool is not possib le, the cause is probably an
l Malfunction of wiring harness or connector
open circuit in the ABS-ECU power circuit or an ope n circuit in the diagnostic output
circuit.l Malfunction of ABS power relay
l Malfunction of ABS-ECU
,
l connector and
Continuity between the following
ABS-ECU
to Data link
connector side
23-8
OKNGMeasure at ABS-ECU connector lDisconnect the connector and mea-sure at the harness side.
N G Repair
l Ignition switch ON
l Voltage between terminal 18 and
bodv around. Check trouble symptom.
I positive voltage
OKCheck the harness between No
NG
Measure at ABS-ECU connector
lDisconnect the connector and mea-sure at the harness side.lContinuity between terminals and body ground.OK:
Repair
l
OKNG Repair
OK
Check trouble symptom. Replace the ABS-ECU.
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ABS Troubleshooting
INSPECTION PROCEDURE 3
ignition key is turned to “ON’? (engine stopped),ProbableABS warning light does not illuminate
[Comment]When power is supplied to the ABS-ECU, the valve relay changes from to OFF ON by the initial check, and thus even if there is a problem with the circuit betweenABS warning light and ABS-ECU, the light will illum inate once when the valve relayis OFF.Accordingly, the cause of the light not illuminating is probably an open circuit in the
light power circuit, a blown light bulb, or an open circuit in both the circuit between
the ABS
liaht and the ABS-ECU and the circuit between the ABS
l Blown fuselBurntout light. bulblMalfunction of wiring. or connector
.
light and the relay.When other lights also do not illuminate, the cause is probab ly a blown fuse.
N GNG ,
Measure at combination meter connector Checkl and l Disconnect the connector and mea-
l Disconnect the connector and mea-
sure atthe combination meter side.
l Continuitv between terminals
OK Continuity
OK
Not
Replace combination meter.
, Check the harnesses between the valve relay and the combination meter,
a n d b e t w e e n t h e A B S - E C U a n d
combination meter (common section).
Repair, if necessary.
INSPECTION PROCEDURE 4
Even after the engine is started, the ABS warning l ight Probable cause ,
remains illuminated.
[Comment]There is probably a short in the ABS light illumination l Malfunction of meter
l Malfunction of valve relay
l Malfunction of ABS-ECU
l Malfunction of wiring
NOTE
This trouble symptom is limited to cases where comm unication with the scan tool is
supply is normal) and the diagnostic trouble code is a normal diagnostic trouble code.
Disconnect the ABS-ECU connector Short circuit inside the combination meter or in the Does the ABS warning light remain illuminated? between the combination meter and the ABS-ECU.
NO
Replace the ABS-ECU.
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