Community Forums

Mr. Banker · 06-21-2022, 08:17 PM

Got this MIL “solid” notification on the dash just now. Searched on the web and it seems it is the dreaded DEF head issue, but if any of you could confirm that would be great. I’m currently in Smelterville ID and it looks like the nearest Cummins service is 90 behind me in Spokane WA.

Any guidance would be appreciated especially if it is safe to drive this back or do I need to get it towed? I fueled in the last 30 miles at a Maverick truck stop and also added DEF there at the pump. I’m wondering if the DEF was contaminated?

Thoughts?

Kevin

BRodgers · 06-21-2022, 10:59 PM

The MIL light is a malfunction indicator light and not specific to the DEF system. During my two DEF head problems there was another indicator light which was specific to the DEF system in addition to the MIL light.

If you have a DEF head problem continuing to operate your coach could put you in limp mode.

On my coach there are two buttons under the speedometer. Pushing both simultaneously brings up a menu where I can find error codes. A call to chassis support at Tiffin will give you a lot of information and advice regarding your problem, whether to continue operating your rig, and resolution of the problem.

Mr. Banker · 06-22-2022, 06:35 AM

Quote:

Originally Posted by Mr. Banker

Got this MIL “solid” notification on the dash just now. Searched on the web and it seems it is the dreaded DEF head issue, but if any of you could confirm that would be great. I’m currently in Smelterville ID and it looks like the nearest Cummins service is 90 behind me in Spokane WA.

Any guidance would be appreciated especially if it is safe to drive this back or do I need to get it towed? I fueled in the last 30 miles at a Maverick truck stop and also added DEF there at the pump. I’m wondering if the DEF was contaminated?

Thoughts?

Kevin

Awesome information, thanks so much. I love this form with so many informed individuals like yourself.

So I did as you stated and the error code is ECM SPN 111 FMI 4. Google tells me this sis a coolant issue. I am calling Rredbay now to confirm.

Thank you,

Kevin

BradS · 06-27-2022, 09:44 AM

Have you checked the sight glass in the engine compartment near the radiator cap where you add coolant? I was having to add coolant (about 1 gal / year) to keep it full. Didn't seem right to me.

Turns out the transmission cooler was leaking. It was replaced under warranty, but recently it also began leaking. Now out of warranty, Tiffin provided another part, but I had to install (or have it installed) on my own. Seems like everything is OK again... at least for awhile.

Dsrtrider · 06-27-2022, 10:02 AM

what level should the coolant be in sight glass when cold?

Warhorse6 · 06-27-2022, 11:53 AM

Should be in the middle of the glass window. I had the same issue about 3 months ago. Took it to Cummins and they didn’t have the sensor but said it was ok to drive, which I did for nearly a mont. Most annoying thing was the light in the dash. When the part came in, was a 30 min or less job to install. Could have done that myself. As you look at the fill tank, sensor is on the top right. Disconnect the quick fastner and reconnect it to see if it clears. Sometimes the connection comes loose. Sensor was about $100 if memory is correct

Mike8253 · 06-28-2022, 06:29 AM

Quote:

Originally Posted by Mr. Banker

Got this MIL “solid” notification on the dash just now.

Kevin

A little off topic, but my 1st thought when I saw the thread title was "What a great idea to have a Mother-in-law warning light on the dash!". Just sayin...