MITSUBISHI GALANT 1989 Service Repair Manual

AUTO-CRUISE CONTROL
SYSTEM - Troubleshootina13-359
10. CHECKING THE CIRCUITS RELATED TO THE OVERDRIVE-CANCELLATION FUNCTION\
<A/T>
$;c;tly switch
+ c
Overdriveswrtch
4
Auto-cruiseT-kcontrol unitliIV
I
Cruise-control
(14)
m34,:
4 A/T
control
module
13A0379
Description of operation
This is a function that cancels the overdrive function for a
certain fixed period of time, if during constant-speed travel in
overdrive, the actual vehicle speed decreases to less than the
vehicle speed retained in the memory. and then after a short
time causes the vehicle speed to return to the vehicle speed
retained in the memory.
Overdrive is
cancelled under the following conditions.
If, during constant-speed travel, the actual vehicle speed
decreases to 7 km/h (4.4 mph) or more below the set vehiclespeed.Under either of the conditions described above, the overdrive-ON signals output from the microcomputer (with the controlunit) are no longer output, and transistor Tr, is switched OFF.As a result, transistor Tr2 is also switched OFF, causing the
current passing through the overdrive switch of the selector
handle to be interrupted at transistor Tr2. with the result that thedrive is controlled at 3rd gear.
Troubleshooting hint ECU terminal voltage
h I
ITerminalSignalIConditions
TerminalNo.voltaoeI
104 A/T controlWhen the overdriveBatterymoduleswitch is switched positiveON.voltage I
11CIIt;riveWhen the overdrive
Batteryswitch is switchedpositiveON.voltage
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13-360AUTO-CRUISE CONTROL SYSTEM - Troubleshooting
11. CHECKING THE THROTTLE POSITION SENSOR AND CLOSED THROTTLE POSITION S\
WITCH
CIRCUIT
<DOHC Engine> (12)
Auto-crursecontrol unit
I 2EB16 I
lntr’
(18)
MFI controlmodule1380424
<SOHC Engine>(12)
<up to 1992Auto-crurse
models

>
control
unrt
I f
Throttleposrtronsensor
Closed throttle-position swrtch
(18)MFI controlmodule
<1993models

>
13A0425(12)Auto-cruise
control unit
Throttleposition
sensorClosed throttle ‘position
switch
(18)MFI controlmodule13A0428
Description of operation
The throttle position sensor and closed throttle position switchare mounted in the idle speed control motor position sensor Orthrottle body and are sensors in the MFI system. The closed
throttle position switch is turned OFF when the accelerator
pedal is pressed and ON when it is released. In addition, throttle
position sensor output voltage varies according to the degree of
opening of the throttle valve.
Troubleshooting hint
<Throttle position sensor>
Diagnostic-No.17
<Closed throttle position switch>
Diagnostic-No.1 7
ECU terminal voltage
TerminalNo.
4
5 Signal
Conditions
Terminal
voltage
Closed throttle When accelerator Battery
position switch
-pedal is pressedpositive voltage
When accelerator
pedal is releasedov
ThrottleWhen accelerator 4.0v-5%’position sensorpedal is pressedall the way down
When accelerator 0.48~0.72v
pedal is released
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AUTO-CRUISE CONTROL SYSTEM - Troubleshooting13-361
Wi
thscan tool
With voltmeter
Auto-cruise control
\
Data link
connector
III
n
,
/r-I
/Ground161009
Data link
connector
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On-board diagnostic checking is performed when there has
been an automatic cancellation, without cancel switch opera-
tion.
(1) The following two methods can be used for checking the diagnostic. Note that the data link connector is locatedunder the driver’s side instrument panel.
@ If a scan tool is used
Connect the scan tool’s socket and connector to the
cigarette lighter socket and the data link connector, and
set the tester. Use the tester according to its operation
instructions; display the diagnostic trouble code num-
ber and then check.
@ If a voltmeter is used Connect a voltmeter between the ground terminal and
the terminal for auto-cruise control of the data link con-
nector.
It is possible to discover which circuit is the cause of
the cancellation by verifying the indication shown by
the voltmeter with the display patterns shown on the
next page.
(2) When the diagnostic trouble code No. is displayed, check by referring to the check chart applicable to that number.
NOTE
Canceling the diagnostic trouble codes
The diagnostic trouble codes remain in memory until the battery is turned off but they can be canceled in the follo-
wing ways without disconnecting the battery terminals.
@ By turning on the ignition switch.
@ By turning the main switch ON while the SET switch is ON and then, within 1 second, turning the RESUME
switch ON. (Put into condition for input check recep-
tion).
@ By turning ON the SET switch and stop light switch at the same time and continuing the ON condition for 5
seconds or more.
@I By checking that the diagnostic trouble codes are canceled using a scan tool or voltmeter.

13-362AUTO-CRUISE CONTROL SYSTEM - Troubleshooting
DIAGNOSTIC DISPLAY PATTERNS AND TROUBLE CODES Code Display patterns (output codes)
No.(use with voltmeter)
11
xJa-.tu
Probable causeCheck chart No.
Abnormal condition of actuator drive systemNo.5<Electrical type>
Abnormal condition of auto-cruise vacuum
pump drive system <Vacuum type>
1212vAbnormal condition of vehicle-speed signal No. 4systemov/
13"12vLow-speed limiter activation (The system is -normal if it can be reset.) <Electrical type>
ov
14*12v14Automatic cancellation activated by vehicle -speed reduction. (The system is normal if it
ov can be reset.) <Electrical type>
15"12v15Control switch malfunction (when SET and No.2, 3
RESUME switches switched ON simul-
ovtaneously)
16"Cancel switch ON signal input (including inputNo. 6-1, 6-2. 6-3
12v16wirings damage or disconnection, or problemin circuitry within the control unit) <Electrical
ov
we>
Abnormal condition of auto-cruise control unit-
17"12v17Throttle position sensor malfunctionNo. 11
Closed throttle position switch malfunction
ov
NOTE
1. Codes indicated by the * symbol are displayed, if the conditions are satisfied, even if the system is
normal. In either case, the system is normal if it can be reset. If ther\
e is an automatic cancellation not
intentionally made by the driver, however, excluding cancellations explicitly made by the
cancel
procedure, there may be a temporary malfunction such as poor contact of \
a harness connector even
though the system can be reset, and for that reason it is necessary to c\
heck according to each individual check chart that is applicable.
ON
OFF
-
Display when vehicle speed is less thanapproximately 20 km/h (12 mph), or before
the auto-cruise control system is set
0.5 set
++P5 setDiagnostic trouble codes are displayed when, after cancel-
lation of the auto-cruise control system, the vehicle speed
decreases to less than approximately 20 km/h (12 mph),
and are canceled by turning OFF the battery or canceling
the diagnostic trouble codes. (Refer to
P.13-361.) <Va-
cuume type> 03ROlS6
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2.Diagnostic trouble codes are displayed when, after cancel-
lation of the auto-cruise control system, the vehicle speed
decreases to less than approximately 20 km/h (12 mph),
and are erased by switching OFF the ignition switch or the
main switch. <Electrical type>

AUTO-CRUISE CONTROL SYSTEM - Troubleshooting13-363
With scan toolri++, lighter ;
03A0258
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After the diagnostic trouble codes in the memory are
erased, if (when the power supply of the electronic controlunit is switched ON once again) the power supply of the
electronic control unit is normal, the on-board diagnostic
output code display will be as below, regardless of
whether the system condition is normal or not.
@ If a scan tool is used: “NORMAL!!” will be displayed.
@ If a voltmeter is used:Continuous ON/OFF signals will be displayed at 0.5
second intervals.
(Refer to the figure at the left.)
INPUT CHECKING
Input checks should be made when the auto-cruise control
system cannot be set and when it is necessary to check
(when a malfunction related to the auto-cruise
contra! system
occurs) whether or not the input signals are normal.
NOTE
1. If inspection of on-board diagnostic is necessary, confirm diagnostic trouble code first and conduct input check.
2.Input check can be conducted by set operations. On-board
diagnostic terminal outputs display patterns.
3.Display codes are displayed only if the circuit is normal ac-
cording to the conditions shown in the table on the next
paw
WITH SCAN TOOL
(1) The setting of the scan tool is the same as for the on-board diagnostic check.
(2) Turn the ignition switch to ON and switch OFF the main switch.
(3) Select the cruise control system from the scan tool’s menu.
(4) With the set switch ON, switch ON the main switch, and
then, within one second, switch ON the resume switch.
(5) Select the diagnostic trouble code from the scan tool’s
menu.
(6) Perform each input operation according to the input check table (on the next page) and read the codes.
(7) Switch the main switch OFF.
WITH VOLTMETER
(1) The voltmeter is set in the same way as for the on-board diagnostic check.
(2) Turn the ignition switch to ON and switch OFF the main switch.
(3) With the set switch ON, switch ON the main switch, and then, within one second, switch ON the resume switch.
(4) Perform each input operation according to the input check
table (on the next page) and read the codes.
(5) Switch the main switch OFF.

13-364AUTO-CRUISE CONTROL SYSTEM - Troubleshooting
INPUT CHECK TABLE
Code Display patterns (output codes) Input operationCheck resultsNo.(use with voltmeter)
21SET switch ONSmE,: switch circuit nor-
RESUME switch ON RESUME switch circuit
normal
23
<Electrical type> <Electrical type>
Each cancel switch ONEach cancel circuit nor-
1. Stop light switch (brake pedalmal
depressed)<Vacuum type>
2. Clutch pedal position switch(clutch pedal depressed)
St;p light switch nor-
<M/T
>
3. Park/neutral position switch
(shift lever to “N” range)
<A/T
>
<Vacuum type>
Stop light switch ON (brake pedal
depressed)
24
25
n r
Driving at approximately to 40 When both No.4 and
km/h (25 mph) or higherNo.5 can be confirmed,
vehicle-speed sensor
circuit normal.
n r
Driving at less than approximately
to 40 km/h (25 mph) or stopped
26I. Clutch pedal position switchsNJFy;h pedal depressed)
2. Park/Neutral position switch
ON (shift lever to “N” or “P”
range) <A/T>
Clutch pedal positionswitch, park/neutral position switch normal
28Throttle position sensor output
voltage over 1.5V (when the ac-celerator pedal is pressed more
than half way)
$yro;e position sensor
Closed throttle position switch Closed throttle position
OFF (accelerator pedal depressed)switch normal
NOTE1. Each code will be displayed in an order of priority beginning from No\
. 1.If there is no display, it is possible that there is a malfunction of th\
e ECU power-supply circuit or the SET and/orRESUME switch, so check according to check charts 1.2 and 3 (P.13-339,340,341,354,355).2. Continue each input operation until the output code is emitted.If no output codes are emitted for inputs even though the display patter\
n is repeated two or more times, there is amalfunction of the switch sensor.3.When each input operation is performed and the signals for the condition\
s are received by the computer, eachoutput code will be repeatedly displayed in the sequence of priority for\
as long as that signal continues.4.If, during the display of output codes, the input operation is canceled \
(if, for example, the SET switch is set from ONto OFF), the code will be displayed for one cycle of the display, but w\
ill not be displayed during the next cycle.This makes it possible, therefore, to check the OFF condition (existenc\
e of not of a short-circuit of the input line orthe switch).
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AUTO-CRUISE CONTROL SYSTEM - Troubleshooting13-365
AUTO-CRUISE CONTROL RELATED HARNESSES
<ENGINE COMPARTMENT>
<INSIDE THE CABIN>
16AO621
1 - Starter motor 7 - Clutch pedal position switch 14 - Overdrive switch2 - Park/neutral position switch8 - Column switch
15 - Control harness and body harness coupling
3 - Actuator <Up to 1990 models>, 9 - lgnrtion switch
16 - Control harness and body harness CouplingAuto-cruise pump10 - Stop light switch 17 - Diode <Up to 1990.5 models><From 199 1 models>11 - Accelerator control unit16 - MFI control module4 - 4 A/T control module12 - Auto-cruise control unit
5
- Combination meter13 - On-board diagnostic output
6 - Combination meterterminal
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13-366AUTO-CRUISE CONTROL SYSTEM - Troubleshooting
<Engine>
SOHC
<Up to 1992 models>
w ,-,’<:
z
\ ‘8.-.-,‘I\ 1:FI ‘iiI -I \’1: j\\dd
/T&Jq
< 1993 models>
DOHC
[Front side view1-.._ -.-- ~
l’e‘--
??A-
‘LA
\\/’ w 36AO175
19 - Throttle position sensor
20 - Idle speed control motor position sensor
21 - Closed throttle position switch
22 - Throttle position sensor (Closed throttle position switch)
36AO303
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AUTO-CRUISE CONTROL SYSTEM - Troubleshootinn13-367
LOCATION OF CONTROL UNIT
w
16AO406
GROUND POINT
JUNCTION BLOCK p-;a
Front
harness
t
Instrument
Roof
harnessr’ II
Ji
-I
$!&;Ipanel
harness Body
harness
z$gger ~----#$jfiillITiHeater- relav
7
J
fuses)
16A0002m36I
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13-368AUTO-CRUISE CONTROL SYSTEM - Troubleshooting
AUTO-CRUISE CONTROL COMPONENTS LOCATION
NOTEThe “Name” column is arranged in alphabetical order. <Engine compartment>
SOHC DOHC
07AOO35
<Interior>
13A0218
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i