Mitsubishi 3000GT 1991, Service Manual

Page: 267 / 1146

CRUISE CONTROL SYSTEM Troubleshootina
Trouble symptom
l
The set vehicle speed varies
greatly upward or downward.
l
“Hunching” (repeated
nating acceleration and
deceleration) occurs after
setting is made.
Probable cause
Check chart No. Remedy
Malfunction of the vehicle No. 4 Repair the vehicle speed
speed sensor circuit
sensor system, or replace
the part.
Malfunction of the
speedometer cable or
speedometer drive gear
turbo>
Vacuum pump assembly No. 5 Repair the actuator
circuit poor contact
system, or replace the
part.
Malfunction of the
vacuum pump assembly
(including air leaks from
negative pressure
passage)
The cruise control system is not
canceled when the brake pedal
is depressed.
Malfunction of the ECU Replace the ECU.
Brake switch (for cruise No. 6
Repair the harness or
control) malfunction
replace the stop light
(short-circuit) switch.
Vacuum pump assembly No. 5 Repair the harness or
drive circuit short-circuit replace the vacuum pump
assembly.
The cruise control system is not
canceled when the clutch pedal
is depressed.
(It is canceled, however, when
the brake pedal is depressed.)
Malfunction of the ECU Replace the ECU.
Damaged or disconnected If the input check
Repair the harness, or
wiring of clutch switch code No. 26 indicates
repair or replace the
input circuit a malfunction. switch.
No. 7
Clutch switch improper
installation (won’t switch
Malfunction of the ECU
Replace the ECU.
The cruise control system is not
Damaged or disconnected If the input check
Repair the harness, or
canceled when the shift lever is
wiring of inhibitor switch code No. 26 indicates
repair or replace the
moved to the “N” position.
i n p u t c i r c u i t
a malfunction. inhibitor switch.
(It is canceled, however, when
No. 8
the brake pedal is depressed.)
Improper adjustment of
inhibitor switch
Cannot decelerate by using the
SET switch.
Malfunction of the ECU
Temporary damaged or
disconnected wiring of
control switch input
circuit
No. 2
Replace the ECU.
Repair the harness or
replace the control switch
Vacuum pump assembly No. 5
Repair the harness or
circuit poor contact
replace the vacuum
assembly.
Malfunction of the
vacuum pump assembly
Malfunction of the ECU
Replace the ECU.
NOTE
ECU: Electronic control
Revision