Engine warning light on-limp when mode towing trailer?

I have a 2013 144" low roof crew model. Only has 35,700 miles. Going to Vegas for a trade show towing a 14' utility trailer with two motorcycles and some trade show materials. About 80 miles outside of Vegas, for no apparent reason, (meaning no harsh acceleration or steep uphill) the engine light comes on and the van goes into limp mode. Made it to Vegas, had to unload the trade show stuff and bikes, dropped trailer. Was heading to the MB dealer to run diagnostic on fault code and light mysteriously disappears. Now I had just refueled and added Diesel Kleen cetaine boost additive. So I chalked it up to some prior bad fuel. This was last Wednesday. Van ran perfectly for the next couple days.

Coming home, SLC, first 100 miles all is well. Then again, light goes on and limpy limpy. This was Sunday so no service places open. Make it home OK, but slow going. I call local MB dealers just to check fault code but can't get in anywhere until tomorrow. After I dropped trailer, van seems to be running fine?!? Engine light is still on, but I only drove it 4 miles after dropping trailer.

Here's my question, can putting additional stress on the engine, say from towing a trailer, trigger the engine light and limp mode? One thing I may mention is that I also have a slightly larger circumference tire than stock; 235/85-16 diameter 31.7, v. 245/75-16 diameter 30.5". I'm wondering also if tire circumference may have any consideration??

Thanks for any input.

It's the trailer wiring. Check it over carefully for a short or grounding.

The only logical course of action is have the vehicle interrogated by appropriate diagnostic tool. Otherwise, it will be a guessing game. Double checking grounding can't hurt. Is this a factory or aftermarket trailer retrofit?

It is an aftermarket trailer retrofit hitch from U-Haul. Four pin adapter to 7 pin. But again, even with the trailer now detached, engine light is on. Hope to get to dealer tomorrow.

The engine light will stay on until the codes are cleared, the trailer lights would have caused it to happen not the fuel.
You need to buy a Sprinter specific scanner so you can read and clear codes.

slupcho said:

It is an aftermarket trailer retrofit hitch from U-Haul. Four pin adapter to 7 pin. But again, even with the trailer now detached, engine light is on. Hope to get to dealer tomorrow.

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I just recently read that it's not recommended by Mercedes-Benz to tap into wires, if this was what was done. Unfortunately, I read it in a Mercedes-Benz technical publication on the computer and, unlike a book, I can't remember where!

Tooth Fairy said:

The engine light will stay on until the codes are cleared, the trailer lights would have caused it to happen not the fuel.
You need to buy a Sprinter specific scanner so you can read and clear codes.

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Initially, when the light was on in Vegas, after detaching the trailer and refueling, adding Deisel Kleen, the light went off.

Bobnoxious said:

I just recently read that it's not recommended by Mercedes-Benz to tap into wires, if this was what was done. Unfortunately, I read it in a Mercedes-Benz technical publication on the computer and, unlike a book, I can't remember where!

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I've towed this trailer. loaded, dozens of time prior to this. Not sure why it is happening now???

I would hazard a guess that you have a very slight boost leak causing LHM with the added load of the trailer.

Do you have a ScanGauge II, UltraGauge or other OBDII type readout? If so what Boost or MAP are you running at when it trips into LHM?

Check all your turbo hoses for signs of oil leaks, splits or loose clamps.

And finally get a scan as even with the light out this will likely tell you what caused the LHM.

Keith.

Agree ^^^^^^^^^ second place is some sort of EGR issue, which should show up with the scan.

Thanks for the comments. I changed the fuel filter, as I am unsure if it had ever been changed, van now at 35,700. Light is currently off and all systems seem to be functioning as normal. I'll schedule for a scan as I would really like to know what contributed to the limp mode.

slupcho said:

Thanks for the comments. I changed the fuel filter, as I am unsure if it had ever been changed, van now at 35,700. Light is currently off and all systems seem to be functioning as normal. I'll schedule for a scan as I would really like to know what contributed to the limp mode.

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I would request the following print-out to give you an idea about Exhaust Gas After-Treatment System health.

https://sprinter-source.com/forum/showpost.php?p=553198&postcount=98