Idle Control System
System Troubleshooting Guide
NOTE:
Across each row in the chart, the sub-systems that could be sources of a symptom are ranked in the order they should
be inspected, starting with . Find the symptom in the left column, read across to the most likely source, then refer to
the page listed at the top of that column. If inspection shows the system is OK, try the next system , etc.
If the idle speed is out of specification and the Malfunction Indicator Lamp (MIL) does not blink code 14, go to inspec-
tion described on page 11-88.
PAGE SUB-SYSTEM
SYMPTOM
DIFFICULT TO START
ENGINE WHEN COLD
WHEN COLD FAST IDLE OUT OF
SPEC (1,000-2,000 rpm)
ROUGH IDLE
WHEN WARM RPM TOO HIGH
Idle speed is
below specified
rpm (no load)
Idle speed does
not increase after
initial start up.
WHEN
WARM
RPM
TOO LOW
On models with
A/T, the idle
speed drops in gear
Idle speeds drops
when air
conditioner in ON or
OFF
Idle speed
fluctuates with
electrical load
WHILE
WARMING UP
FREQUENT
STALLING
AFTER
WARMING UP
FAILS EMISSION TEST
IDLE
ADJUST-
ING
SCREW
IDLE AIR
CONTROL
VALVE
AIR
CONDI-
TIONING
SIGNAL
ALTER-
NATOR
FR
SIGNAL
NEUTRAL
SWITCH
SIGNAL
(M/T)
STARTER
SWITCH
SIGNAL
FAST
IDLE
THERMO
VALVE
HOSES
AND
CONNEC-
TIONS
CLUTCH
SWITCH
SIGNAL
(M/T)
AUTOMATIC
TRANSAXLE
GEAR
POSITION
SIGNAL
102 88 90 92 94 96 98 100 101
System Troubleshooting Guide
NOTE:
Across each row in the chart, the sub-systems that could be sources of a symptom are ranked in the order they should
be inspected, starting with . Find the symptom in the left column, read across to the most likely source, then refer to
the page listed at the top of that column. If inspection shows the system is OK, try the next system , etc.
If the idle speed is out of specification and the Malfunction Indicator Lamp (MIL) does not blink code 14, go to inspec-
tion described on page 11-88.
PAGE SUB-SYSTEM
SYMPTOM
DIFFICULT TO START
ENGINE WHEN COLD
WHEN COLD FAST IDLE OUT OF
SPEC (1,000-2,000 rpm)
ROUGH IDLE
WHEN WARM RPM TOO HIGH
Idle speed is
below specified
rpm (no load)
Idle speed does
not increase after
initial start up.
WHEN
WARM
RPM
TOO LOW
On models with
A/T, the idle
speed drops in gear
Idle speeds drops
when air
conditioner in ON or
OFF
Idle speed
fluctuates with
electrical load
WHILE
WARMING UP
FREQUENT
STALLING
AFTER
WARMING UP
FAILS EMISSION TEST
IDLE
ADJUST-
ING
SCREW
IDLE AIR
CONTROL
VALVE
AIR
CONDI-
TIONING
SIGNAL
ALTER-
NATOR
FR
SIGNAL
NEUTRAL
SWITCH
SIGNAL
(M/T)
STARTER
SWITCH
SIGNAL
FAST
IDLE
THERMO
VALVE
HOSES
AND
CONNEC-
TIONS
CLUTCH
SWITCH
SIGNAL
(M/T)
AUTOMATIC
TRANSAXLE
GEAR
POSITION
SIGNAL
102 88 90 92 94 96 98 100 101