Heavy vibration when I turn on engine brake

CAT might do it different than Detroit. I might be remembering it wrong, but Detroit use to use the center 2 cylinders for low, the front 2 and back 2 for med (middle 2 off), and all 6 for high. If it does it on all 3 settings, then my advice doesn't help much. Kinda odd.

 

I was taught that jakes rotates. Not cylinder specific. 1 cylinder, 2 cylinders, 3 cylinders.

I also have a 07 w9. The truck is VERY picky about the quality of fuel. And vibrates when it hates the fuel. Does both jakes AND full throttle modes. Some poor fuels aren't as bad as others.

As for pulling the codes. Turn cruise switch off. Hold the resume switch down about 5 seconds. Engine light will flash. Count the flashes. 5 flashes with a breif pause and 5 more flashes. You'll always get a code 55. If the light is off. That's standard operating procedure. Everything is working. If the light is on, It'll flash whatever codes you got ACTIVE. My common numbers are 93 and 94. Intake valve actuators for cylinders 3 and 4. It's been a few months for me now so the problems must be fixed. FINALLY.

 

93 and 94 are supposed to be cylinders 3 and 4. And might not be the actuators but the plugs themselves. I know the actuators were never replaced. And if you dig in to google enough. There's posts of wiring issues.

 

You don’t need to read the flash code while it’s happening. It stored it in the computer for you. Turn key on, make sure cruise control is switched to “off” then just hold down “resume” switch until the 2 digit flash codes start flashing via check engine light

 

It stores codes in computer but only flashes ACTIVE codes. So if the problem happens to be working. No code will flash.

 

I understand that. But the active code he had just for that minute will be stored and will be first code to be spit out when he pulls codes with cruise control. I had same issue with my cat today. I have old stored codes. I had a situation arise where it only happens on occasion. Check engine light started flashing a code. I shut the truck down and pulled code. Gave me the latest code first. If it was active only for a second, but problem fixed, it will be stored and will be first code to be emitted

 

Mine don't flash anything unless it's active. Triggering the light.

 

Oh these cats are good like that. If code is active. It will flash. If it problem is not active anymore, it will store the code in sequence till codes are deleted with et