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The Dreaded Onan Fault Code 27

September 07, 2016, 10:21:11 pm

Hi folks,

My Onan 8K genset has about 300 hours on it. Have had no problems until today, with all routine service (oil change, filter, etc.) done at MOT.

I started it today to perform a weekly load run with the AC's while we are between trips. It started with no problem, but I was outside the coach about three minutes later and noticed the generator had stopped running. Went back inside and saw a fault code of 27 on the wall display. Started the generator back up. It runs fine, but is not providing any electrical power.

Some online research led to discussions about a PMA (Permanent Magnet Alternator) lost fault, which does not sound good at all. Does not seem to be a job I could tackle and the parts which may need to be replaced run into at least a couple of coach bucks. Ouch.

The only difference in my symptoms seems to be the fact that my generator starts up and runs fine. The discussions in the limited research I have done seem to center on the fact that the generator stops, displays this 27 fault code, and then won't start.

Anyone here run across this before? Didn't see anything in a search of the forum, so I thought I would throw this out.

I'm also checking to see if there is any fuse that I should inspect. I know that's not what the code discussions have referenced so far, but the symptoms sure seem to point to a sudden and complete disconnect of generating power even thought the generator is purring along quite fine.

I think I'm going to have to find someone to service the Onan here in Northern Virginia. Too long to wait until my next visit to MOT in December.

Rats.


Don

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Re: The Dreaded Onan Fault Code 27

Reply #1 – September 08, 2016, 07:00:27 am

Don,
I would be thinking of Cummins Factory Shop in Richmond, 804 232-7891, They have a great shop for the RV units and more important, their tech is very sharp.  I'd call them.
Cummins has owned Onan for <25 yrs.

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Re: The Dreaded Onan Fault Code 27

Reply #2 – September 08, 2016, 10:38:50 am

Dave,

That's exactly the kind of info I was hoping to get. Have tried to use some local shops for basic maintenance needs (LOF, etc.) and have been stunned at the lack of interest and inflated cost. And no one had a good reputation.

I think I'm going to see if I can get it in to them ASAP.

Many thanks, Dave!

Don

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Re: The Dreaded Onan Fault Code 27

Reply #3 – September 08, 2016, 11:27:04 am

Dave knows what he knows, generators are his baby for sure.
JohnH

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Re: The Dreaded Onan Fault Code 27

Reply #4 – September 08, 2016, 12:46:02 pm

There is a new dummy shop in manassas that would be closer. Also one in Winchester that was started by the generator techs out of cloverdale.

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Re: The Dreaded Onan Fault Code 27

Reply #5 – September 08, 2016, 12:47:33 pm

Finally there is communication vehicle specialists in Chantilly ant they mostly work Onan but also work on Powertech.  I was very happy with their service and the tech has about 20 years experience on generators.

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Re: The Dreaded Onan Fault Code 27

Reply #6 – September 08, 2016, 04:43:48 pm

I don't know about the Onan but I used to look after welding machines on pipelines and the permanent magnets would go out or change polarity and I use a 12 volt battery and would jump the fields and that would fix the magnet. I hope it is as simple for you

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