2005 Beaver Patriot; Check engine light comes on, coach goes into slow mode, then returns to normal.

[Neil Loveless]

I'm wondering if any of you experienced folks out there can help me out with an annoying and potentially dangerous situation, I was cruising down Rt. 75 toward Tampa doing about 68-70 mph when the check engine light came on and the coach went into slow mode running 45.  I managed to get to an off ramp about a mile down the road when the check engine light went out and all was normal the rest of the way.  Same thing happened again on Rt. 75 north heading home, this time the check engine light went out while I was still on the road and I was able to get home without further issue.  Last year coming home from NY state the same thing happened on Rt. 95 in GA, I got off the road, shut the coach off and restarted and all was normal.  It seems I have some sort of intermittent glich probably in a computer that monitors all the systems.  In each case everything was normal (oil pressure, engine temp., tranny temp, oil pressure, etc.).  I know that intermittant things can be hard to detect, but can someone point me in the right direction?  Thanks for any tips!

[DavidL]

You should get a scan tool compatible with your CAN bus / powertrain and find out why the motor derated.  Before you get stuck when the problem gets worse.

Most of the time, the Engine ECU / Transmission ECU monitor and put the Diagnostic Trouble Code (DTC) into history.

Edited November 8, 2023 by DavidL

[Tom Cherry]

6 minutes ago, Neil Loveless said:

I'm wondering if any of you experienced folks out there can help me out with an annoying and potentially dangerous situation, I was cruising down Rt. 75 toward Tampa doing about 68-70 mph when the check engine light came on and the coach went into slow mode running 45.  I managed to get to an off ramp about a mile down the road when the check engine light went out and all was normal the rest of the way.  Same thing happened again on Rt. 75 north heading home, this time the check engine light went out while I was still on the road and I was able to get home without further issue.  Last year coming home from NY state the same thing happened on Rt. 95 in GA, I got off the road, shut the coach off and restarted and all was normal.  It seems I have some sort of intermittent glich probably in a computer that monitors all the systems.  In each case everything was normal (oil pressure, engine temp., tranny temp, oil pressure, etc.).  I know that intermittant things can be hard to detect, but can someone point me in the right direction?  Thanks for any tips!

Many probably have.  There are two basic ways.  Some, as David suggests, purchase a scanning device and then work their way through the codes and then figure out how or what to fix.  

The other is to go to a Cummins Authorized repair facility and have the “computer” or the Electronic Control Module (ECM) scanned using the Cummins software, Insight.  That shows every event…as probably one of the scanners may, and but then gives more information and codes as to what caused it….then the techs follow the diagnostics and check those devices.

That also then, if you ask, will get you an electronic copy, which you can print out, so a tech can finish programming a new ECM, should you ever need one.

We have a few folks that are as knowledgeable or more so than the average Cummins tech and can sort out and explain the Cummins information If you have the codes and history, they often chime in.

Just a matter of your skill set and the understanding of what a purchased scanner will give…which is not as detailed as the Cummins scan….and how you want to approach.  It MAY be a simple connection.  Intermittent issues, that “self correct, are baffling.  But, if derating or partially shutting down the engine gives temporary relief or temporarily fixes a bad sensor, then odds are….it will fail….big time….and you might need a tow.  SUPPOSITION….but has happened.

You need facts and information….do it yourself or find a Cummins shop.  The history is there….and totally readable from the ECM.  A consumer device works well if you understand what the codes are and google and research….  And many are successful.  The other way is also what many choose.

. 

[cbr046]

If you read your manual there's a procedure to retrieve DTC's through the engine diagnostic switch.  It's a start . . . .

- bob

[jacwjames]

AGREE with scan tool and or a monitoring system.  Hard to fix something if you don't know what is going on. 

I have a Silverleaf VMSpc which isn't sold anymore but it monitors the paramiters that I want to watch but also will provide diagnostics for fault codes.  I had trouble my last trip and it showed a 94/10 fault code which was abnormal fuel pressure.  In some instances it would derate the engine.  A search on the Cummins Quickserve site gave me some things to check and I was able to fix the problem (fingers crossed). 

Look at either the Scangauge and/or the Bluefire. 

[philcarrell]

Have you changed fuel filters lately, if so, do the above mentioned tests.

 

[Neil Loveless]

Thank all of you for your great input, you've provided much needed advice, I really appreciate it!

 

[1nolaguy]

As a follow up to Phil Carrell's comment, if you have not recently changed your fuel filters when was the last time they were changed? Reduction in fuel because of fowled filters can cause these symptoms too.

[Neil Loveless]

Thanks for commenting, the first time I experienced this issue was 8/28/22, I had full service performed on 9/29/22 including all filters, and the 2 recent occurances were on 10/28/23 so just over 1 year, and approx. 2,300 miles driven since service.  Do you think this could have been the filters?

[Frank Bergamo]

Have you checked the coolant level and the coolant sensor? If it was a fuel problem I don’t think it would have derated after changing fuel filters unless you have algae in fuel. You could try changing filters again, if you do cut open the old ones to see if there is algae present. Also, I believe you have a Cat motor, so all the Cummins stuff is not applicable. Hope this helps.

[jacwjames]

If it's been over a year since changing fuel filters you could pull the primary filter (if you have two) and inspect the top of the filter for signs of algae.

It doesn't take long for algae to bloom in a tank under the right circumstance and or picking it up at fuel station. 

I had it and it almost choked off my fuel supply.  After that I started using Biobor and Startron enzyme treatment.   Never had another problem.

[Dennis H]

Your best solution is to visit a Cummins repair shop. Their software is superior to any of the scan tools out there. They will scan your coach and give you a printout of all past and present codes and tell you what they mean. They'll also clear all past codes and offer to fix whatever is causing your issue. Mine turned out to be a bad smog control device. I also had an issue with the bolts loosening on the turbo which triggered the check engine light. IMO, get it fixed before you end up stranded somewhere where you don't want to be.....Dennis