6 - 20
FI
FUEL INJECTION SYSTEM
Fault code No.
37
Symptom Engine speed is high when the engine is idling.
Diagnostic code No. d54
ISC valve
Order Item/components and probable
cause
Check or maintenance job
Reinstatement
method
1
Backup fuse is blown.
• Check the backup fuse.
Refer to “CHECKING THE
FUSES” in chapter 3.
ISC valve
returns to its
original position
by turning the
main switch to
“ON” and back
to “OFF”.
Reinstated if the
engine idle
speed is within
specification
after starting the
engine.
2
Throttle valve does not fully close.
• Check the throttle body.
Refer to “THROTTLE BODY”.
• Check the throttle cables.
Refer to “ADJUSTING THE
THROTTLE CABLE” in chapter
3.
3
ISC valve is stuck fully open due to
disconnected ISC unit hose or cou-
pler. (High engine idle speed is
detected with the ISC valve stuck
fully open even though signals for
the valve to close are continuously
being transmitted by the ECU.)
• Check that the ISC unit coupler
is not disconnected.
• The ISC valve is stuck fully open
if it does not operate when the
main switch is turned “OFF”.
(Touch the ISC unit with your
hand and check if it is vibrating
to confirm if the ISC valve is
operating.)
4
ISC valve is not moving correctly.
• Execute the diagnostic mode.
(Code No.d54)
• After the ISC valve is fully
closed, it opens to the standby
opening position when the
engine is started. This operation
takes approximately 12 seconds.
Start the engine. If the error
recurs, replace the throttle body
assembly.
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