Page 566 of 1216
14-112AUTO-CRUISE CONTROL SYSTEM - Troubleshootina
Trouble symptomProbable causeCheck chart No.Remedy
l The set vehicle speed variesMalfunction of the vehi-No.4Repair the vehicle speec
greatly upward or downward.cle speed sensor circuitsensor system, or re-l “Hunching”
(repeated alternatingplace the part.
acceleration and deceleration)Malfunction of the
occurs after setting is made.speedometer cable orspeedometer drive gearAuto-cruise
vacuumNo.5Repair the auto-cruise
pump circuit poor con-vacuum pump, ortactreplace the part.Malfunction of the
auto-
cruise vacuum pumpMalfunction of the
ECU-Replace the ECU.
The auto-cruise control system is notDamaged or discon-If the input check codeRepair the harness or
canceled when the brake pedal isnetted wiring of theNo. 23 indicates a mal-replace the stop light
depressed.stop light switch inputfunction. No. 6switch.circuit; brake switch (forauto-cruise control) mal-function (short-circuit)Auto-cruise
vacuumNo. 5Repair the harness or
pump drive circuit short-replace the auto-cruisecircuitvacuum pump.Malfunction of the
ECU-Replace the ECU.
The auto-cruise control system is notDamaged or discon-If the input check codeRepair the harness, or
canceled when the clutch pedal isnetted wiring of clutchNo. 26 indicates a mal-repair or replace the
depressed. (vehicles with a manualswitch input circuitfunction. No. 8clutch switch.
transaxle)(It is canceled, however, when theClutch switch improper
brake pedal is depressed.)installation (won’tswitch ON)Malfunction of the
ECU-Replace the ECU.
The auto-cruise control system is notDamaged or discon-If the input check codeRepair the harness, orcanceled when the shift lever isnetted wiring of inhibi-No. 26 indicates a mal-repair or replace the in-
moved to the “N” position. (vehiclestor switch input circuitfunction. No.7hibitor switch.llvith an automatic transaxle)
[It is canceled, however, when theImproper adjustment of
Drake pedal is depressed.)inhibitor switchMalfunction of the
ECU-Replace the ECU.
Cannot decelerate by using the SETTemporary damaged orNo. 2Repair the harness orswitchdisconnected wiring ofreplace the SET switch.SET switch input circuitAuto-cruise
vacuumNo.5Repair the harness orpump circuit poor con-replace the auto-cruisetactvacuum pump andactuator.Malfunction of the auto-cruise vacuum pump
and actuator (includingclogging of negativepressure passage)Malfunction of the
ECU-Replace the ECU.
Page 567 of 1216
.z
c-AUTO-CRUISE CONTROL SYSTEM
- Tr6ubleshootina
Trouble symptom
Cannot accelerate or resume speed
by using the RESUME switch.
Probable cause
Damaged or discon-netted wiring, or short-circuit, of
RESUMEswitch input circuit
Remedy .’ ’-c liiCheck chart No.,;+ >,, a”:; : :
9 . /~ A%No.3.Repair theharness‘&
replace the RESUMEswitch.Auto-cruise
vacuumNo. 5Repair the harness orpump circuit poor con-replace the auto-cruisetact
vacuum,pump andactuator.Malfunction of the auto-cruise vacuum pumpand actuator (includingair leak from negativepressure passage)Malfunction of the
ECU.-Replace the ECU.
Auto-cruise control system can beMalfunction of theNo.4Repair the vehicle-set while
traveling at a vehicle speedvehicle-speed sensorspeed sensor system,
of less than 40 km/h (25 mph), orcircuitor replace the part.there
is no automatic cancellation atthat
speed.Malfunction of the‘I,speedometer cable orthe speedometer drive6 i
gear
The indicator light of combination
meter does not illuminate.
(But auto-cruise control system is
normal.)Malfunction
of control function by
ON/OFF switching of ELC 4 A/T
accelerator switch,Non-operation of damper clutch,
2nd gear hold, etc.)3verdrive
is not canceled during
‘ixed speed driving.
10 shift to overdrive during manual
driving. Malfunction of the
ECU-Replace the ECU.
Damaged or discon--Repair the harness or
netted bulb of indicatorreplace the bulb.light
Harness damaged ordisconnected
‘._,.Malfunction of circuit
re-No. 9Repair the harness or
lated to acceleratorreplace the part.switch
OFF functionMalfunction of the
ECUMalfunction of circuit
re-No. 10Repair the harness or
lated to overdrive can-replace the part.
cellation, or malfunction
of ECU
Page 571 of 1216
i-._AUTO-CRUISE CONTROL SYSTEM
- Troubltyshootf$6. CHECKING THE STOP LIGHT SWITCH CIRCUIT
Sub fusible link @
vacuum
w-vStop light
Auto-cruisecontrol unit13A0366Description of operation
When the brake pedal is depressed during constant-speedtravel, the stop light switch’s (NC) contacts for the cruise-control system open, with the result that the current to the
auto-cruise vacuum pump is interrupted, thus canceling the
constant-speed travel.
At the same time, moreover, the closing of the (NO) contacts
for the stop light results in the sending of the cancel signal to
the control unit, so that the auto-cruise vacuum pump current is
discontinued within the control unit, thereby canceling the
constant-speed travel.
The flow of current is from the sub fusible link
@I to fuse No. @
of the junction block, the stop light switch, and the control unit.Troubleshooting hint
ECU terminal voltage
TerminalSignal
No.
15
t-i-
Stop light
switch (load
side)pedal is depressed.
NOTENC: Indicates ON at all times. (For cruise contra!)NO: Indicates OFF at all times. (For stop light)l,_7. CHECKING THE INHIBITOR SWITCH CIRCUIT
Auto-
cruise
controlunit
Vehicles with x
theft-alarmIVehicles without5 theft-alarm systemsystem br
*Theft-’ nI Ialarm, ._I
starterz
relayQlOF: N A_ 3
Inhibitor
switchDescription of operation
The inhibitor switch also functions as the switch for the starter.If the selector lever is moved to the “N” position during
constant-speed travel, current flows to the control unit, inhibitorswitch, theft-alarm starter relay (vehicles with theft-alarm
system), starter motor, and to ground; the cancel signal istherefore input to the control unit, thus canceling the constant-speed travel.5Troubleshooting hint
ECU terminal voltage
TeE!alSignalConditionsTerminalvoltage
1Inhibitor switchAt all timesSystemvoltage
C.starter
motor13A036BNOTERefer to GROUP 8-Theft-alarm System forthe + (asterisk) on“Theft-alarm System”.
Page 575 of 1216
AUTO-CRUISE CONTROL SYSTEM - Troubleshooting'14421
16A065i
Auto-cruise
16LOOS
SELF-DIAGNOSIS CHECKSelf-diagnosis checking is performed when there has been an
automatic cancellation, without cancel switch
operati’on.(1) The following method can be used for checking the
diagnosis. Note that the diagnosis check connector is
located under the driver’s side instrument panel.
Connect a voltmeter between the ground terminal and the
terminal for auto-cruise control of the diagnosis check
connector.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 diagnosis code No. is displayed, inspect accord-
ing to the inspection chart No. related to each code No.
NOTECanceling the diagnosis codes
The diagnosis codes remain in memory until the battery is
turned off but they can be canceled in the following ways
without disconnecting the battery terminals.
1. By turning on the ignition switch
2.By turning the cruise switch ON while the SET switch is ONand then, within 1 second, turning the RESUME switch
ON. (Put into condition for input check reception)
3.By turning ON set SET switch and stop light switch at the
same time and continuing the ON condition for 5 seconds
or more.
4.By checking that the diagnosis codes are canceled using avoltmeter.
Page 578 of 1216
14-124AUTO-CRUISE CONTROL SYSTEM - Troubleshooting
INPUT CHECK TABLE
CheckInput operationiI!eDisplay patterns (output codes)Check results
No.(use with voltmeter)
1SET switch ON21X:Gayitch circuit
2RESUME switch ON2212vRESUME switch cir-cuit
normalov
3Stop light switch ON (brake23
pedal depressed)
;;pl;yht switch
4Driving at approximately to 4024When both No. 4
km/h (25 mph) or higherand No. 5 can be
co,nfirmed, vehicle-.speed sensor circuit
5Driving at less than approx-2512vnormal.
imately 40 km/h (25 mph) or
stopped
ov
61. Clutch switch ON (clutch26Clutch switch inhibi-
pedal depressed) tor switch normal
2. Inhibitor switch ON (shift12vlever to “N” or “P” range)ov
-aIT>
7Throttle position sensor output28
voltage over 1.5V (when theThrottle positionsensor normal
accelerator pedal is pressedmore than half way)
?Idle switch OFF (accelerator29Idle switch normal
pedal depressed)
NOTE
1.Each code will be displayed in an order ofpriority beginning from No. 1.
If there is no display, it is possible that
there is a malfunction of the ECU power-
supply circuit or the SET and/or RESUMEswitch, so check according to check
charts
1,2 and 3.
2. Continue each input operation until the
output code is emitted.
If no output codes are emitted for inputs
even though the display pattern is repe-
ated two or more times, there is a
malfunction of the switch sensor.
3.When each input operation is performed and
the signals for the conditions are received by
the computer, each output 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 ON to OFF), the
code will be displayed for one cycle of the
display, but will not be displayed during the
next cycle.
This makes it possible, therefore, to check
the OFF condition (existence of not of a
short-circuit of the input line or the switch).
Page 579 of 1216
Page 580 of 1216
Page 581 of 1216
AUTO-CRUISE CONTROL SYSTEM - Troubleshooting
--
Auto-cruise indicator light
Vehicle speed sensor
(Reed switch)WA0728
l/4’NTj$trol unit-
