FUEL INJECTION SYSTEM
8-57
Fault code No. 37 Symptom Engine speed is high when the engine is idling.
Diagnostic code No. 54 ISC valve
Order Item/components and probable
cause
Check or maintenance job Reinstatement
method
1 Throttle valve does not fully close. • Check the throttle bodies.
Refer to “THROTTLE BODIES”
on page 7-6.
• Check the throttle cables.
Refer to “ADJUSTING THE
THROTTLE CABLE FREE
PLAY” on page 3-7.
ISC valve re-
turns to its orig-
inal position by
turning the
main switch to
“ON” and back
to “OFF”.
Reinstated if
the engine
idling speed is
within specifi-
cation after
starting the en-
gine.
2 ISC valve is stuck fully open due to
disconnected ISC unit coupler. (High
engine idling 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 to
“OFF”.
(Touch the ISC unit with your
hand and check if it is vibrating
to confirm if the ISC valve is op-
erating.)
3 ISC valve is not moving correctly. • Execute the diagnostic mode.
(Code No. 54)
• After the ISC valve is fully
closed, it opens to the standby
opening position when the en-
gine is started. This operation
takes approximately 12 sec-
onds. Start the engine. If the er-
ror recurs, replace the throttle
body assembly.
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