Adjust the engine idle speed periodically on the engine at normal operating temperature.
To adjust the idle speed:

Engine oil and filter change
Throtile cable playDTC “c46” (p1657-h/l or p1658): excv
actuator circuit malfunction
Detected condition
Possible cause
C46
The operation signal does not reach the
excv actuator.
Excva position sensor voltage low or
high
0.14 V ≤ Sensor voltage < 4.9 V
(without the above range)
excva can not operate properly.
Excva ...
Engine components removable with the
engine in place
Engine components which can be removed while the engine is installed on the
frame are as follows. For the installing
and removing procedures, refer to respective paragraphs describing each
component.
Center of engine
Item
Removal
Inspection
Installation
...
Diagnostic information and procedures
Drive chain and sprocket symptom diagnosis
Condition
Possible cause
Correction / reference item
Noisy drive chain
Worn sprocket
Replace
Worn drive chain
Replace
Stretched drive chain
Replace
Too large drive chain slack
Adju ...