Small Engine

Small Engine Troubleshooting Problems? Ask a Mechanic Now.

Ask an Expert,
Get an Answer ASAP!

Rv onan generator question, it won't run and the code comes…

Customer Question
Rv onan generator question...

Rv onan generator question, it won't run and the code comes up #27, voltage sense fault

Mechanic's Assistant: What's the make and model of the generator? And can you guesstimate how old it is?

Onan, 4000...model number is ***** 11 years on our rv.

Mechanic's Assistant: Do you plan on doing the work yourself?

Not sure....it says the controller is unable to sense the output voltage and I don't know where the controller is?

Mechanic's Assistant: Anything else we should know to help you best?

No, that's it

Submitted: 10 months ago.Category: Small Engine
Show More
Show Less
Ask Your Own Small Engine Question
Answered in 18 minutes by:
9/27/2017
Technician: Wayne, Engine Rebuilder replied 10 months ago
Wayne
Wayne, Engine Rebuilder
Category: Small Engine
Satisfied Customers: 11,303
Experience: many years on egine rebuilding, lawn mower,roto tiller,Truck,and small engines
Verified

Hi I'm Wayne

I will help you with this

let me look that code up

Ask Your Own Small Engine Question
Technician: Wayne, Engine Rebuilder replied 10 months ago

HI

The code 27 that you say was given means that the A1 control is not detecting AC voltage, which in most cases is because it is not producing any AC voltage. If the A1 control does not detect AC voltage it will not run.

. Check the brushes, Check the wiring going to the brushes, the plug on the A1 control. The control is directly behind the start switch on the genset.Remove the battery cable and the screw beside the battery post. Lift up on the box to unhook the clips a the top. Pull it out. The larger box behind is the A1 control. Remove the three bolts holding that box in, unhook the plug. There are two screws in the box attaching it to the control itself take them out and slip it out of the box.

I hope this helps you

Hi. If this helped you Please rate my answer 4 or more stars. That is the only way I get credit for the questionor the money you paid stays at JA and I get nothing for my time.If you need more info use the REPLY buttonNot the Poor/Bad service.

Wayne
Ask Your Own Small Engine Question
Customer reply replied 10 months ago
Can I get to it without dropping the generator out of the rv?
Customer reply replied 10 months ago
no phone call
Technician: Wayne, Engine Rebuilder replied 10 months ago

Hi

Yes follow the directions

Wayne

Ask Your Own Small Engine Question
Technician: Hank F., Technician replied 10 months ago
Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 15,979
Experience: Certified on Onan and Generac generators
Verified

Sir, my name is ***** ***** I am going to assist you with this.

You have been given completely incorrect information. The previous post was geared to an HGJ series genset. It will not work on your KY series.

The brushes and brush leads on this unit are not accessible without removing the genset from the coach, and disassembling it. The brushes are located inside, behind the flywheel.

The first thing you need to do is to verify if the genset is actually producing voltage or not.

On the left side of the genset, coming out of the base toward the front of the unit, there is a gray 1" conduit. This conduit is about 3 feet long. Follow it to where it goes.

If it leads to a junction box under your coach, open that junction box.

Connect a voltmeter across the white and black wires, and press and hold the start button to keep the engine running for a few seconds. Note the voltage.

How much voltage is there showing?

If your conduit goes up through the floor of the coach, we need to take a slightly different approach.

On the panel that holds the start/stop switch, there are 2 - T30 Torx bolts that hold a plastic cover in place. Remove those 2 screws, and pull the plastic cover straight up and out.

There are 4 screws holding the control panel in place - one on the right side (it also holds a black wire), one on the left side going in through the divider, and 2 from the outside at the front of the base. Remove all 4 screws, and wiggle the control panel out. It is a very tight fit, but it will come out.

Once you have the panel out, you will need to reattach that black wire with one of the screws.

Connect one lead of your voltmeter directly to the back of the circuit breaker, and make sure the circuit breaker is on.

Connect the other lead of the meter to a good engine ground.

Press and hold the start button for a few seconds, and note the voltage.

How much voltage is showing?

Ask Your Own Small Engine Question
Technician: Hank F., Technician replied 10 months ago

Have you tested the voltage yet?

Ask Your Own Small Engine Question
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a technicianLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask Hank F. Your Own Question
Hank F.
Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 15,979
15,979 Satisfied Customers
Experience: Certified on Onan and Generac generators

Hank F. is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future.

JimmyBagley, IA

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

< Previous | Next >

Meet the Experts:

Curtis B.

Curtis B.

Technician

15,517 satisfied customers

have worked on and around most engine models for 35 yrs./Polaris ATV expert

Rick

Rick

Factory Authorized Trainer

4,218 satisfied customers

Outdoor Power Equipment technical trainer since 1990, covering eight states.

Jon K.

Jon K.

Small Engine Diagnostic Expert

2,995 satisfied customers

Gold certified Stihl tech, Service Manager for a rental/repair shop.Certified in most small engines

James W

James W

Small Engine Troubleshooting Expert

2,986 satisfied customers

7 years as Mechanic & Parts Manager for Brother who has Owned Lawn & Garden Repair shop for 35 years

Vince O.

Vince O.

Small Engine Technician

2,927 satisfied customers

Over 30 years experience repairing lawn and garden equipment. Chainsaws, mowers,blowers and trimmers

Wayne

Wayne

Engine Rebuilder

11,303 satisfied customers

many years on egine rebuilding, lawn mower,roto tiller,Truck,and small engines

RUSS

RUSS

SERVICE TECHNICIAN

1,723 satisfied customers

28 YEAR SERVICE TECHNICIAN

< Previous | Next >

Related Small Engine Questions
My Onan 3600 LP is flashing error code 27. What are my
My Onan 3600 LP is flashing error code 27. What are my options? … read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
My Onan diesel 5MDKBH generator was running fine, I shorted
My Onan diesel 5MDKBH generator was running fine, I shorted out the output wires, the generator stopped running. On trying to restart, I get code 27. The output at the ac sense measures 2 ohms. The ge… read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
I have an Onan generator on my RV. It starts but will not
I have an Onan generator on my RV. It starts but will not keep running. The fault code (45) says controller unable to sense quadrature frequency. How do I get it fixed. … read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
My Onan Micro Quite 4000 generator is turning itself off,
My Onan Micro Quite 4000 generator is turning itself off, unable to continue to run, and the computer monitor system is showing a code that says it #14"OverFrequency Fault" Engine governor unable to m… read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
I'm having some technical issues with a 4kyfa spec p.fault
Good afternoon, I'm having some technical issues with a 4kyfa spec p.fault code27 showed on the diagnostic. Have found this much so far: stator tested good Swapped out control unit with older but same… read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
I have an RV with a Onan generator Model GN 480 (5500
I have an RV with a Onan generator Model GN 480 (5500 watts). It is dead. If you hit the switch on the driver's console or even on the start switch on the generator itself there is no response. Not ev… read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
onan 4000 flashing code 33gen will not stay started.
onan 4000 flashing code 3 gen will not stay started. More information: Fault code 45: Controller unable to sense quadrature frequency.… read more
Expert
Expert
I have a onan microquiet 4000 4kyfa26100k spec k with code
I have a onan microquiet 4000 4kyfa26100k spec k with code 27, before code set and generator stopped working, it was producing 140-150 volts 55hz, replaced controller no change, have manual but have n… read more
Expert
Expert
I have an Onan 5.0 MDKBH Generator. Anyone had hands on experience
I have an Onan 5.0 MDKBH Generator. Anyone had hands on experience troubleshooting the electrical side?… read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
i have an onan rs 12000 that runs for 2 seconds and shuts off.
i have an onan rs 12000 that runs for 2 seconds and shuts off. It has a fault code 27. whats wrong… read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
My Onan 5MDKBH-5238A 120V generator starts and the shuts down
My Onan 5MDKBH-5238A 120V generator starts and the shuts down immediately. The fault code is 27 - Loss of AC voltage sense. The two sense wires are connected firmly at the breaker and modular plug int… read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
I got an old 7.5kw Onan Generator, and the 4 wires connected
I got an old 7.5kw Onan Generator, and the 4 wires connected to the voltage adjustment panel got disconnected, I need to know how (in what order )to re connect them.The # XXXXX F2, F1, 2, 1,The wires … read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
have12.5 kw onan generator starts and run for two minutes then
have12.5 kw onan generator starts and run for two minutes then quits. gives me a 27 code where to look first… read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
My onan generator for my 1998 Four Winds Majestic RV is not
My onan generator for my 1998 Four Winds Majestic RV is not working. The generator starts but won't power the microwave, AC, heater, fridge. It was working the last time we took it out. All of a sudde… read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
I have an Onan Rv generator that will not turn on. i took it
I have an Onan Rv generator that will not turn on. i took it the a shop and a reading indicates code 45-speed fault as cause. What can I do to repair this?… read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
Onan microlite 4000 - Model# 4KY FA26100J S/N# F990 934964
Onan microlite 4000 - Model# XXXXX FA26100J S/N# XXXXX 934964: generator just quit while running normal. engine will not re-start or crank over. Oil level is normal. Spark plug+air filter chaged 42 ho… read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
We r in omaha Nebraska and our generator stopped running.
We r in omaha Nebraska and our generator stopped running. It starts for a couple of seconds but then dies. The indicator light on the start button (on the generator) blinks three times indicating "ser… read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
I have an onan 4000 microquiet that is showing a code 27. I
I have an onan 4000 microquiet that is showing a code 27. I took it to a cummins dealer and they wanted $800 to replace carb, fuel filter, air filter, and adjust valves. HOW does a code 27 suggest thi… read more
Hank F.
Hank F.
Technician
High School or GED
15,979 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x