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ATC Indicator Light


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Our first trip out with this new to us coach went fairly well. One concern is the ATC indicator light would start flashing a series of rapid flashes. Then stop for a while then do it again. It seems to flash more as the day got hotter. It was a balmy 114 degrees in Mesquite NV. Anyone else experience this issue?

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I don't know if newer coaches are any different, but when this happened to me (random, infrequent flashes) it turned out to be a clogged primary fuel filter.  2003 Cummins ISC

The fix was easy but it took me a few thousand miles to figure out what was going on.  Eventually (after ignoring it for a few trips) I could turn on the ATC light on upgrades by how much throttle was applied.  On the last return trip the coach started losing power (fuel starvation) and upgrades became a serious hazard. 

- bob

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When the ATC light comes on, the first thing you should do is to change the fuel filters.

The engine and transmission computers talk to each other.  When the engine is not producing the targeted amount of power based on throttle position and load, the transmission will turn off the ATC system and the ATC light will come in.  In most cases, changing fuel filters will fix the problem.

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I changed both fuel filters when I first picked up the coach. This Dynasty sat in one spot for at least 1 1/2 years, maybe two. It had a half tank of fuel when I picked it up. Since the fuel filter change I have run about 150 gallons through it. I did add fuel treatment for water and fuel mold grow. Maybe a clinker worked itself down the line. Now that the fuel filter has been mentioned, I think it comes when under load as in going up hill???🤨

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4 minutes ago, Gary 05 AMB DST said:

Robert and Aimee, Doesn't the ATC light refer to automatic traction control? Did you accidently turn on the ATC on the console switch? Do you have the owner's manual?

Gary 05 AMB DST

No accident and yes, the owners manual talks about how ATC works and nothing about fuel starvation.  Owner's manual isn't very helpful in this case, maybe even misleading. 

3 minutes ago, Nevada Rob said:

 I think it comes when under load as in going up hill???🤨

EXACTLY!  and it will get worse (trust me on that one).  Mine started toward the end of a 625 mile trip and didn't think much about it.  On the return leg (another 625 miles) the transmission would downshift with cruise control on and a little more ATC light on upgrades, but still intermittent.  Next trip, a short 400 mile trip (both ways) I didn't notice it much, probably because the DW was with me.  The final trip, 430 miles one way, it was noticeable with power still seemingly available, but on the way home (430 miles) it kept getting worse and worse and I was lucky to maintain 45 mph on the slightest upgrades.  The more throttle the worse it got.  I was using the boost gauge to determine how much throttle it could handle, and 10 lbs of boost was all she would do.  Momentum was my friend. 

Go out and give it full boost and see what happens.

Best,

- bob

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2 hours ago, Gary 05 AMB DST said:

Robert and Aimee, Doesn't the ATC light refer to automatic traction control? Did you accidently turn on the ATC on the console switch? Do you have the owner's manual?

Gary 05 AMB DST

Gary I did not turn on the ATC at that time. I play with it later and the light on the dash with ATC activated is a steady light. What I am talking about is a series of 10 flashes that are very quick or blinking. The owners manual does talk about the ATC switch and how to use it. Trouble shooting problems based on info in the owners manual is another matter. This forum has more great info in one day that the owners manual have.

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Posted (edited)

This exact same scenario happened to me after taking on a bad tank of fuel in the Yukon unbeknownst to me. After Googling the symptoms once we got back into the states I found another Monaco owner that had the same exact symptoms. That night I did the Googling after our generator and Aqua-Hot quit also. The next morning we drove directly to the nearest truck repair shop and had them change out ALL diesel fuel filters and the rest is history. Everything worked great after that. I am now extremely careful about where I purchase fuel and I always use a combination of Diesel Kleen & Biobor JF maintenance dose to my tank before it sits for any length of time. While traveling I will use it about every other tank or so.

Haven't had any more ATC blinking lights on my dash ever again.

Edited by Dr4Film
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Mine happened at the height of the Colonial Pipeline ransom outage where locating fuel in the Eastern US was darn near impossible.  I ended up filling the tank at my local Ingles supermarket before the trip, which had been around 1/4 tank for 3 weeks.  Just the fact they had diesel might indicate they didn't get much activity.  Between the Ingles and letting my tank sit near empty I'm thinking I picked up some growth.  My other fuel stop was at a TA Truck stop on the way up.  The engine was acting up and it was late night so I didn't want to stop on the way home.  Fuel mileage was phenomenal (10.6 mpg)!  When I got back the fuel in the filter was pretty dark with contaminants floating around in it.  I still haven't changed the secondary filter (but I carry a spare). 

Years ago I witnessed a friend that filled up at a no-brand truck stop, basically a run down station on the interstate.  He spent half a day trying to get it started, including spraying ether in the intake.  He pumped a bunch of water out.  I vowed then to always get fuel at a high volume branded station . . . . and that was years before I bought my first diesel powered vehicle.  Some lessons stick with you.  The best lessons are witnessed, not experienced. 

- bob

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