Cat C15 operating questions

[Khein]

Guys I have 2 questions about Cat C15 operation
First of all I want to ask what's the variable valve actuator for. I dont know what is it for, I know it works with inlet valves, and think it works as a brake, but usually I see this in the escape valves and not in inlet. Please help me to understand this.

Another question about C15 engines is that I want to know what is the inlet valve actuator test. I have try it with ET and is sayd "Not OK" in several cilinders but I really don't know what it means.

Thank you in advance.

[cnckulp]

The variable valve actuator are also called IVA (intake valve actuator). IVA's are used for emission. Cat calls it a controlled Cyl. burn. IVA's can hold the intake valve open once it is already open, but can't open the valve if it is closed. As for the IVA test (Not OK) that cyl. is not working. It could be Adjustment, Bad solenoid or housing.
If you don't have any other codes for IVA's I don't worry about the test.