Visually inspect the isc valve if necessary.

Throttle body inspection and cleaning
Throttle valve synchronizationStarting the engine
Before attempting to start the
engine, make sure:
The transmission is in neutral.
The engine stop switch is in
the "" position.
Note: this motorcycle has a
starter interlock system for the
ignition and starter circuit. The
engine can only be started if:
  ...
DTC “c21” (p0110-h/l): iat sensor circuit
malfunction
Detected condition and possible cause
Detected condition
Possible cause
C21
Output voltage is not with in the following
range.
0.15 V ≤ Sensor voltage < 4.85 V
Iat sensor circuit open or short.
Iat sensor malfunction.
Ec ...
Continuity check
Measure resistance across coupler “b” (between “a”
and “c” in figure).
If no continuity is indicated (infinity or over limit), the
circuit is open between terminals “a” and “c”.
Disconnect the coupler “b” and measure resistance
between couplers “a” and “b-1”.
If no continuity ...