Malfunction indicator light on with Check engine indicator flashing

[wagonmaster2]

Decided to take a little trip this week, only second one in 2 years concerning about covid, and after driving about 240 miles and only 3-4 miles from campground I noticed the Malfunction Indicator lamp was on. Since was in heavy traffic the previous 15 minutes not sure exactly when the Lamp came on. Then shortly the Check Engine Indicator began flashing for maybe a minute then went off.

But the Malfunction Indicator stayed on, and in the campground I've checked several hours later and it still comes on when the ignition is turned on and it stays on, but no Check Engine Indicator.


My 2015 Dutch Star has little over 27,000 miles on it now, and Freightliner chassis. What should be my first course of action, what might I be expecting, and what could be causing this?

I'll be here for the next week at least, and if I remember right there is a Freightliner shop (not an Oasis unfortunately) about 20-25 miles from the campground. Used them once 17 years ago to replace a leaky flexible exhaust pipe off the engine and it took them all afternoon clear up to way after dark to decide who was going to check it out and do the replacement. Wasn't to impressed with their operation.

[R.Wold]

First thing to do is use your LBCU to read the codes and post them here. There is quite a cadre here that probably knows exactly what is going on and why, but without some specifics, it would be guessing which doesn't do much good. But the few specifics you provided are fairly telling. Waiting for those codes.....

I will say that you can most likely make the 25 miles to the FL shop and you will probably end up there anyway, but it would be helpful to let them know what the issue is (hence the codes request) to make sure they have the parts on hand and make an appointment to minimize the down time.

Also stop cycling your ignition. Don't start engine again until you have to go somewhere. You may be on the way to a derate, or already in the first stage, and ignition cycles accelerate the progression. Just turn the key on once to obtain the codes. If you haven't figured out how access codes yet, consult the book first to familiarize yourself with the process.

[R.Wold]

If you want the best guess, this is it:

https://www.irv2.com/forums/attachme...2&d=1632818180

“When a vehicle equipped with a diesel exhaust fluid (DEF) system sits for an extended period of time, the DEF in the tank may crystallize around the float on the DEF level sending-unit tube and require cleaning. This crystallization may cause the float to stick on the tube.”

But again, codes are crucial to get beyond the guessing stage.

[wagonmaster2]

Originally Posted by R.Wold

First thing to do is use your LBCU to read the codes and post them here. There is quite a cadre here that probably knows exactly what is going on and why, but without some specifics, it would be guessing which doesn't do much good. But the few specifics you provided are fairly telling. Waiting for those codes.....

I will say that you can most likely make the 25 miles to the FL shop and you will probably end up there anyway, but it would be helpful to let them know what the issue is (hence the codes request) to make sure they have the parts on hand and make an appointment to minimize the down time.

Also stop cycling your ignition. Don't start engine again until you have to go somewhere. You may be on the way to a derate, or already in the first stage, and ignition cycles accelerate the progression. Just turn the key on once to obtain the codes. If you haven't figured out how access codes yet, consult the book first to familiarize yourself with the process.

I keep reading about "accessing codes", but I have no idea what, how, or where all this is done. Mechanical things I understand, but dealing with codes so far have lost me. What book are we talking about?

[wagonmaster2]

Originally Posted by R.Wold

If you want the best guess, this is it:

https://www.irv2.com/forums/attachme...2&d=1632818180

“When a vehicle equipped with a diesel exhaust fluid (DEF) system sits for an extended period of time, the DEF in the tank may crystallize around the float on the DEF level sending-unit tube and require cleaning. This crystallization may cause the float to stick on the tube.”

But again, codes are crucial to get beyond the guessing stage.

I just got back from a 2,200 mile trip in September, first in a year. Drained the DEF tank and filled with fresh DEF before leaving, kept the tank above 3/4 the whole trip, filled it before leaving on this trip.
Really appreciate all the information here.

[R.Wold]

You use the little square joy stick on the dash to toggle through the various options on the LCD to find the codes. I don't remember the exact process because I don't do it that way anymore. I use OTR diagnostics and any j1939 compatible code reader will do it for you, but you can also get them right off the dash. Instructions are in the chassis manual.

This should get you there:

https://www.rvtechlibrary.com/electr...bcu_owners.pdf

Also this might be helpful:

https://www.irv2.com/forums/f26/manu...ar-254311.html

Here’s another:

https://dragonship.blog/mysteries-of...bcu-explained/

And its important to remember that you can do everything right and still have emissions system problems.

[arlawbob]

Originally Posted by wagonmaster2

I keep reading about "accessing codes", but I have no idea what, how, or where all this is done. Mechanical things I understand, but dealing with codes so far have lost me. What book are we talking about?

FL has an 800 number. Call it anytime and they can walk you through retrieving the fault codes and diagnose the problem best.

[R.Wold]

right - 1-800-FTL-HELP - always had good experiences with this

[wagonmaster2]

I'll give FL a call. didn't realize they would spend enough time on the phone to get through all that manuavering. Thanks. This problem is a little overwhelming for me and being on cancer medicine getting hot flashes isn't helping the matter any either.


Always felt for the RV owners who got trapped out on the road and what problems they had to overcome and now it's here at home. Only hope is the solution can be handled in one day at the shop.


I would have been up duck creek without a paddle if it hadn't been for this Forum.

[R.Wold]

Originally Posted by wagonmaster2

I'll give FL a call. didn't realize they would spend enough time on the phone to get through all that manuavering. Thanks. This problem is a little overwhelming for me and being on cancer medicine getting hot flashes isn't helping the matter any either.


Always felt for the RV owners who got trapped out on the road and what problems they had to overcome and now it's here at home. Only hope is the solution can be handled in one day at the shop.


I would have been up duck creek without a paddle if it hadn't been for this Forum.

They answered the phone on Christmas day last year when I was derated and had to abandon the rest of my trip. They mean it when they say 24/7. Once you have the codes you’ll likely get more info here - always best to be as informed as possible going in to the shop, especially when out of warranty.

[jerry davis]

Don’t bet on getting the best advice from the Freightliner help line. When my check engine light and warning low def came on the help people said not to worry as it was just a communication problem and continue my trip. 200 miles later when an extremely low def warning came up (def tank was full) they said the same thing. 60 miles later when stop engine and total derate happened they suggested that I leave the ignition on for up to two hours and everything should clear up. Yeah, right. Over night boondock and a 140 mile tow to the nearest Freightliner dealer and two weeks later the coach is waiting for a new DEF head.

The two gentlemen that were my contacts at Freightliner help were JR and Chris. Nice guys but seriously uninformed. Not a happy customer here….

[R.Wold]

Originally Posted by jerry davis

Don’t bet on getting the best advice from the Freightliner help line. When my check engine light and warning low def came on the help people said not to worry as it was just a communication problem and continue my trip. 200 miles later when an extremely low def warning came up (def tank was full) they said the same thing. 60 miles later when stop engine and total derate happened they suggested that I leave the ignition on for up to two hours and everything should clear up. Yeah, right. Over night boondock and a 140 mile tow to the nearest Freightliner dealer and two weeks later the coach is waiting for a new DEF head.

The two gentlemen that were my contacts at Freightliner help were JR and Chris. Nice guys but seriously uninformed. Not a happy customer here….

That is good information and rather disturbing. Fortunately the OP just needs help accessing the DTCs.

[Dutch Star Don]

Just a follow up in case Allen, (wagonmaster2) doesn't get a chance to post right away. He was able to pull the codes via the LBCU and spoke with Freightliner. The codes were related to a fuel issue and will most likely be resolved with a change of filters. He'll change them when he gets home.

[R.Wold]

Good news indeed!