ISL 400 Engine Brake

[twopals]

I own a 2002 Country Coach Intrigue with a Cummins ISL 400 engine. This is my first coach & I'm still learning.

My question is in regards to the engine brake. My coach has a 3 position rocker switch for the brake--upper position is high, center is off & lower position is low.There doesn't seem to be any differemce between hi & low I don't feel that there is any appreciable engine braking in any position. When in hi or low, and I lift off the accelerator the transmission will down-shift to fourth gear---but the coach seems to continue to "coast" not really slowing down much.

I would appreciate any input. Am I using the engine brake correctly? Should the braking be more "aggressive" than I have described?

Thanks,

TWOPALS

[EngineerMike]

I had that condition on my present coach when it was new. Hard to believe its the same problem but not impossible. On mine three ECM plug pins were not fully seated so the chassis harness plug didn't mate w/those 3 pins on the Engine Computer Module (on Rt side of engine, 2 large electrical plugs). Took mfgr's guys coupla days to find it. Knowing where to look this inspection should take no more than 1/2 hour, and will take a trained eye to see the difference in elevation of the pins.

You should be able to notice the difference, low turns 3 of the 6 cylinders into an air compressor; high turns all 6.

[JWT]

If what E. Mike says doesn't work you might have to go to a Cummins dealer to have it re-programed. My Jake brake would work only on the low side, didn't matter if the switch was on low or high.Went to Cummins while we were in Yakima and they re-programed it and been fine every since. It makes a big difference when the high side of the Jake works, good luck.

[Flagelpater]

On my friends 04 Dynasty he needs to also step on a foot switch, with his left foot, much the same as the old Headlight Dimmer Switch. The difference between Hi and Low is significant!

Sorry: I answered an old screen. Did not know the experts were helping already!

[Bob&AnnaMari]

Yes, there is a definite difference on my coach (with ISL 400) between the two settings. But, it takes a good 6% grade to really notice the difference. The low setting will not hold the speed on a 6% grade on my coach, but the high setting will. I would suggest you take your rig to a Cummins dealer and have it checked. I personally would not want to be on an extended 6% grade without my engine brake.