Mitsubishi 3000GT Service Manual page 470

ENGINE AND EMISSION CONTROL - Cruise Control System
Trouble symptom
The set vehicle speed varies Malfunction of the vehicle
l
greatly upward or downward.
l
"Hunting" (repeated alternating
acceleration and deceleration) Malfunction Of
occurs after setting is made.
The cruise control system is not Brake switch (for cruise No.6
canceled when the brake pedal is
depressed.
brake pedal is depressed.)
SET switch.
NOTE
ECU: Electronic control unit
Probable cause
speed sensor circuit
the
speedometer cable or
speedometer drive gear
turbo)>
Vacuum pump assembly No.5
circuit poor contact
Malfunction of the vacu-
um pump assembly
(including air leaks from
negative pressure pas-
sage)
Malfunction of the ECU
control) malfunction
(short-circuit)
drive circuit short-circuit
disconnected wiring of
control switch input circuit
Vacuum pump assembly No.5
circuit poor contact
Malfunction of the vacu-
Malfunction of the ECU
Check chart No. Remedy
No.4
Repair the vehicle speed
sensor system, or replace
the part.
Repair the actuator sys-
tern, or replace the part.
Replace the ECU.
Repair the harness or re-
place the stop light
switch.
Repair the harness or re-
lace the vacuum pump
Repair the harness or re-
place the control switch.
Repair the harness or re-
place the vacuum pump
assembly.
Replace the ECU.
I