The excs is operated by the signal supplied from the ecm. The open/close operation of the excv is performed by the excva which is controlled by the ecm by changing the current direction of the actuator motor. The position sensor (incorporated in the excva) detects the excva movement by measuring the voltage and then the ecm determines the excv opening angle based on the engine rpm and gear positions. Every time the ignition switch is turned on, the excva automatically drives the excv and detects full close/open position voltages and sets the excv to middle position.
Full close

Full open

Exhaust control system descriptionCam chain guide inspection
Inspect the cam chain guide in the following procedures:
remove the cam chain guides. Refer to “cam chain guide / cam chain
tensioner removal and installation” .
Check the contacting surface of the cam chain
guides. If it is worn or damaged, replace it with a new
one.
...
Cylinder head disassembly and assembly
Refer to “engine top side disassembly” .
Refer to “engine top side assembly” .
Caution
identify the position of each removed part.
Organize the parts in their respective groups
(i.E., Intake, exhaust, no. 1 Or no. 2) So that
they can be installed in their original
locations ...
Fuel injector inspection and cleaning
Inspect the fuel injector in the following procedures:
remove the fuel injector. Refer to “throttle body disassembly and
assembly” in section 1d .
Check the fuel injector for evidence of dirt and
contamination. If present, clean and check for
presence of dirt in the fuel lin ...