1991 MITSUBISHI 3000GT display

35-10SERVICE BRAKES -Anti-lock Braking System Troubleshooting
j CONTINUED FROM PREVIOUS PAGE /After a test drive, use self-diagnosis to
P.35-11.).>
1No trouble codes output and normal
codes are displayed?
NoTrouble codes are output
Yes
All ABS functions are normal.
(Nor are there stored memory of
past trouble code.)put terminals and the di-
agnosis check connector.
If trouble does not re-
appear, watch vehicle
movements until it reap-
pears. (Refer to
P.35-12.)
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SERVICE BRAKES -Anti-lock Braking System Troubleshooting
35-11
Adapter
iarness%f&(MB9913771(Mi3991341)\12FOO57
CHECK USING SELF DIAGNOSIS FUNCTION
(1) With the ignition switch OFF, connect the MUT through the
adapter harness
(MB9913771, turn the ignition ON and
select the ABS system. (The ABS warning light lights up, it
goes into the MUT mode. In the MUT mode, ABS does
not function.)
If it does not go into the MUT mode, check the ECU power
circuit and the harness between the ECU and diagnosis
check terminals.
(2) Read the diagnosis output codes from the ECU memory.
(3) Clear the diagnosis codes once from memory. (Refer to
P.35-12.)If the memory cannot be cleared, the ECU is currently
detecting the trouble and the ABS ECU is in fail safe. If it
can be cleared, the trouble is either temporary or appears
only when driving.
(4) When the trouble codes cannot be cleared, or when the
ABS ECU goes into fail safe during another test drive and
trouble codes are output, check according to trouble code
check charts (E-l-E-6).
DIAGNOSIS CODE CHART
Diagnosis codeCheckReferenceDiagnosis codeCheck
Referencechart namepagechart namepawNo. MUT display lettersor remedyNo. MUT display lettersor remedy
L11FR SNSR. OPEN41FR SOL. VALVE
12FL SNSR. OPEN42FL SOL. VALVEE-4P.35-23E-lP.35-2013RR SNSR. OPEN43REAR SOL. V.
14RL SNSR. OPEN51VALVE RELAYE-5P.35-24
15VEH. SPD. SNSR.E-2P.35-20 52MOTOR RELAYE-6P.35-25
22STOP LAMP SWE-3P.35-2055 CONT. UNITECU-
replacementI
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35-12SERVICE BRAKES -Anti-lock Braking System Troubleshooting
METHOD OF CLEARING DIAGNOSIS
ACTUATOR TEST FUNCTION
CODE MEMORYThe actuator can be forcibly driven in the following
Cautionway by using the MUT.
lWhen servicing is finished, clear the diagno-
sis code memory.NOTEd
lThe actuator test cannot be carried out when the
Trouble codes cannot be cleared from memoryABS ECU system is in fail safe.
when the ABS ECU system is in fail safe. Proceed tol When using forced drive using the MUT, the
diagnosis and repair.vehicle must be stopped.
(1) Clear memory using MUT.
lDuring forced drive using the MUT, forced drive
(No. 7
“DIAG. ERASE” in the actuator test isoperation is stopped when any wheel speed
selected to erase the diaanosis code.)reaches 10 km/h (6 mph).
(2) After clearing, recheck the diagnosis codes, and
check that memory is cleared.
Actuator test specifications
No.MUT display
01FR VALVE A
02
FL VALVE A03
REAR VALVE A04
FR VALVE M
05
FL VALVE M06
REAR VALVE MDrive solenoid
valve and motorDrive pattern
Not used
Solenoid valve and
pump motor for
each HU corres-
ponding channel.

Start of forced drive
End of forced drive
1440588
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35-20SERVICE BRAKES -Anti-lock Braking System Troubleshooting
the following diagnosis codes are displayed “11 FR SNSR. OPEN”
“12 FL SNSR. OPEN” “13 RR SNSR. OPEN” “14 RL SNSR. OPEN”
[Explanation]
The ABS ECU detects breaks in the wheel speed
sensor wire. This trouble code is output if the wheel
speed sensor signal is not input (or short circuited)
or if its output is low when starting to drive or while
driving.[Hint]
In addition to a broken wire/short circuit in the wheel
speed sensor, also check whether the sensor gap is
too large, sensor harness wire is broken, or sensor
harness and body connector are not properly
con-
netted.
r--~- -E-2 When dlagnosls code“15 VEH. SPD. SNSR.” is displayedI[Explanation]
This trouble code is output when there is an
abnormality (other than broken wire or short circuit)
in any of the wheel speed sensor output signals
while driving.
[Hint]
The following can be considered as the cause of the
wheel 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 signal
lSensor output signal is below the standard value
or amplitude modulation is over the standard
value. Using an oscilloscope to measure the
wave shape of the wheel speed sensor output
signal is very effective.l Broken sensor harness
l Poor connection of connector
NOTE(1) If contact is poor, check the sensor cable by
bending and lightly stretching it.
(2) Except for the case where a fault condition
exists in the system, but the inspection results
are normal; if an abnormality cannot be found in
the sensor circuit displayed as abnormal, erase
the diagnosis code and turn the ignition switch
to OFF once, and then test-drive again.
If the same trouble code is output, replace the
ABS ECU. If the trouble does not occur
any-more, the problem is likely to be with the ABS
ECU.(If the trouble is in the speed sensor circuit, but
is difficult to recreate, it will recur even after the
ABS ECU has been replaced.)
SPEED SENSOR
FRONTCLH) FRONTFTRH)RF.AR(LH) REfIR(RH)
@cTJ @ij@ fi&
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35-22SERVICE BRAKES -Anti-lock Braking System Troubleshootin,g
E-3When diagnosis code “22 STOP LAMP SW” is displayed
[Explanation]
The ABS ECU outputs this trouble code in the
following cases.
lStop light switch may remain on for more than
15 minutes without ABS operation.
lThe harness wire for the stop light switch may
be open.[Hint]
!LiIf the stop light operates normal, the harness for the
stop light switch input circuit is broken or there is a
malfunction in the ABS ECU.
r7
ABS-ECU-~
RESISTOR
Ll121314/5161716~9~10111~12~13~14/15(16i~7~1~~'9~20~1~2~2~24~~6~~~~9~30~3~~~~2~~5~
KK35-AK-R3506A
I
Yes6
Repair harness.
Malfunction of ABS ECUReplace ABS ECU.
‘visionI

SERVICE BRAKES -Anti-lock Braking System Troubleshooting35-23
E-4When diagnosis codes “41 FR SOL. VALVE”, “42 FL SOL. VALVE” or
“43 REAR SOL.
V.” are displayed.
iL[Explanation]
The ABS ECU normally monitors the solenoid valve
when turned OFF, the ECU determines the solenoid
drive circuit.
coil wire is broken/short-circuited or the harness is
If no current flows in the solenoid even if the ECU
broken/short-circuited, and then these trouble
turns the solenoid ON or if it continues to flow even
codes are output.
/
ii
LJ
$$l.E#AT'ON;;QO'D
4I
I
i
Ii'-. - - ---i>? 5 3 6
ABS-ECU-A22 Al9 *17 ,IY Y Y Y I
disconnect ECU connector
Yes
The harness wire for the
solenoid valve circuit
whose resistance value is
outside the range of the
standard value is brokenor short circuited.
I
Repair ABS harness.
Malfunction of ABS ECU
1) Replace ABS ECU.
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35-24SERVICE BRAKES -Anti-lock Braking System Troubleshooting
E-5When diagnosis code “51 VALVE RELAY” is displayed
[Explanation]
When the ignition switch is turned ON, the ABS
ECU switches the valve relay OFF and ON for an
initial check, compares the voltage of the signal to
the valve relay and valve power monitor line voltage
to check whether the valve relay operation isnormal. In addition, normally it monitors whether or
not there is power in the valve power monitor line
since the valve relay is normally ON. Then, if the
supply of power to the valve power monitor line is
interrupted, this trouble code will be output.
EPfiiB EenIGNITIONSWITCH(IG1)
COMSINATIONm
I
H” g@J$s2
4:u
,,8I. -----I/IL’ /
IIII
I /IIII/I/-,----__--_,>yo “-a-‘+G ------------------ ?$”:
;’m[1?610 2pEl%zq~,___ ____________~_______~~~~
>;?
$-:dL1:27 =Yi62.G 22 +%!
i.-I
1/2131a)5161718(QIIO(I ~~~2(13~~a~i5~~6/i7~~~IQ$O~Y~2~3~24~~6~~~28~~~1~2~3~4~5~Remove and check the valve relay.
IWhen the valve relay is checked, are
the following conditions found?
No. 85
-No. 86: Resistance
value 60 - 120 fiNo. 30-No. 87a: Continuity
No. 30 - No. 87: No continuity
When battery voltage is applied
between terminals No. 86 and No. 85.
No. 30
- No. 87: Continuity
No. 30 - No. 87a: No continuity
Yes
Install the valve relay and remove
the HU connector.
E+GG-pqReplace valve relay.
&I/ NnIIWith the ignition key “ON”, does the
Is there continuity between HU No. 8
and No. 7 terminals?
IYes
Connect the HU harness and remove
the ECU connector.Faulty harness in HU
1Does resistance between body con-
nector terminal No. 2 and terminal
No. 27 indicate 60
- 120 II
NoMalfunction of harness
between HU and ECU.
Yes
With the ignition key “ON”, does the
voltage between terminal No. 22 and
ground indicate battery voltage?
YesNo
II- Malfunction of harness
between HU and ABS
ECU.Repair harness.
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SERVICE BRAKES -Anti-lock Braking System Troubleshooting
I - IE 6 When diagnosis code “52 MOTOR RELAY” is displayed
[Explanation]
l When the motor continues to revolve
The ABS ECU outputs this trouble code 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 during MUT forced
drive mode, there is a broken or short circuited
motor monitor wire.
lWhen the motor ground line is disconnected and
the motor does not revolve
I Yes I
FUSIBLE LINKa
-_ ------- --10‘5 “1
n.-
7;:? 9rn’E5 u
p?GEilq”~+103 3-_------- --
ES-ECU2526.-
4
-;“I
1112I3/415151713Ig~10~1~~12~19114~15]1~17118j~ls~o~l~e~3~4’415~2T~E~~o~l~~~~~5~(X35-AK-33533Does the motor make a noise
during MUT forced drive modeBroken wire or short cir-
Remove the motor relay and
check resistance values.
No. 85
- No. 86: Resistance
value 30 - 60 fiNo. 30-No. 87: No continuity
Battery voltage is applied
between terminals No. 85 and
No. 86.Replace motor relay.
No. 30-No. 87: Continuity
Yes
Is pump motor ground connected
normally?Connect ground wire.
Yes
Install motor relay and remove
HU connector.
III NoI1Connect the HU connector
and remove the ECU connector
III NoI3Is resistance between body
connector terminal No. 5 and
ground 0.1 -0.3 R?Repair harness.
Yes
ABS ECU malfunction
P Replace ABS ECU.
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