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Pete, Automotive Mechanic
Category: Medium and Heavy Trucks
Satisfied Customers: 27830
Experience:  Performed various automotive repairs on several light duty and medium duty vehicles over 15 years of service.
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I have a cummins Komfort guard apu on my commercial truck. I

Customer Question

I have a cummins Komfort guard apu on my commercial truck. I recently had it serviced. When I got it back, it was throwing codes for "speed sense", "high AC output", & "unknown shutdown". Then shutting off right away. I did get it to stay running for about 45min...since then, it starts but it doesn't seem the system knows it's running. Started sounds engaged, none of the hvac system turns on, running light is blinking as if starting, and it'll then shut off with "start fault " code. Any ideas what's wrong?
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Pete replied 1 year ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

My info is somewhat limited on your model here but I had seen no one else has responded and would like to see if I can help here.If at any time you feel that I cannot help with this please let me know.

If this only occurred after it was serviced I would have the service center re check their work to make sure nothing was damaged in any way or left loose or disconnected that is causing this fault here.This sounds like a wiring fault that was disconnected or damaged causing this issue here needing located and repaired.If the service center is unable to locate the fault or already re checked this let me know so we can continue.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.Thanks Pete.

Customer: replied 1 year ago.
I assumed it was a ground wire or such...checked and all looked well. I then had my mechanic go over his work....he couldn't find anything. He doesn't have much experience with this particular unit and is researching it. It seems the speed sense, high AC output codes, and it now not seeing that the motor is running all relate to whatever gives it the speed of the motor. There is no actual speed sensor. I think it's done through the stator and the control board mounted in the generator housing. I guess it's determining if that's correct....and how to tell if it's the board or the stator. Assuming that is how it "senses" speed.
Expert:  Pete replied 1 year ago.

Unfortunately this is a difficult one for me to answer myself here on this model.If you want I can open this up for others here to see if anyone else has any more info on this just let me know if this is something you would like to do.

Thanks Pete

Customer: replied 1 year ago.
Sure....that'd be great.
Expert:  Pete replied 1 year ago.

I will open your question up for others here to see if someone else can assist further on this as there may be others here that may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.If you feel you want to continue to work with me on this feel free to reply at any time but keep in mind in some cases it can be difficult to fully diagnose or help repair this without seeing your vehicle.

Thanks Pete

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