2004 Volvo having cruise and engine brake issues

not that i know off you can disconnect the air line and see it should be only your second position working on the engine brake then you know if it doesn't act up u know you have a problem from the valve or the cylinder.

 

My engine brake is weak.....
The epg, does that box ever wear out, like the valve doesn't want to close or open all the way, I you can hear air leaking, as soon as you turn off the engine, air leak stops.
While the engine is running the air comes goes, I'm assigning the valve is opening and closing
Is the valve sticking open ? Or is it not closing all the way ?
The dealer wants to replace the epg and electronic board assembly with an air line attach to it.
Which is the problem EPG or the valve assembly that connects to an air line ?

 

Is it a manual transmission? If so pull the clutch up with your toes from the back. The engine break and cruise control could be that the system is sensing that you're on the clutch and doesn't want to engage.

Just a simple suggestion if you haven't tried it.

 

Volvo Usually Does have weak engine Brake but don't replace both valves at once cuz that #### gets expensive, replace the one that supplies the air in my opinion and then replace the EPG but if you can test them, its easier to tell which one is messing up

 

Im pretty sure that your epg valve is either shot or someone disconnected it, volvo engine brake will absolutely never compare to a c15 engine brake, you can change the epg valve and see what happens after that. possible valve adjustment if not done so already, also since you're there change the engine brake valve in the engine it's relatively cheap.

 

you should be able to do them yourself just be careful with the air line going behind the starter you need a 7/8 wrench make sure you remove the line before unbolting the valve that way you avoid breaking the air line. other than that there is one 1/4 airline going to it and a electrical connection and three 12 mil bolts pretty simple the engine brake valve is simple as well need to remove valve cover right in the middle of the engine two 12 mil bolts and two 8 mil holding wires just make sure you put wires back in their place and replace purple o rings

 

Just a thought on your cruise control. I chased my problem for 8 months til I figured it out. Big annoying nightmare. I changed the micro switches on the brake and clutch, clutch spring, signal stalk arm, new tps and speed sensor on tranny. Nothing I did fixed it for more then a week. Back on labour day weekend I took all the battery wires off and the fuses behind the battery and cleaned everything. I got rid of the bars that connect the batteries together and replaced with the thick cable type. I also replaced the ground strap with a new thick cable from the motor to the frame. I coated everything in dielectric grease and tightened everything. Knock on wood but its been over six weeks and no issue. Might be worth spending a couple hours to do all this. It might cure your problem. These trucks can be really finicky if voltage isn't just right. If it doesn't though....its still a good thing to do for your electrical. Good luck. Hope you fix it