CHeck engine light

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JD Sharp

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Ferndale, WA
Yellow check engine light just came on and I don't know how to find fault code. Motorhome is 2012 Tiffin Allegro Red with Cummins ISB engine. There is supposed to be a diagnostic switch on the dash,  but not there. Does anyone have experience on where and how to get fault code?
 

Gary RV_Wizard

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I think a 2012 Red would be a Freightliner chassis, so you can call FCCC Customer service at 1-800-FTL-HELP. Have the last 6 digits on the VIN handy.  On the Freightliner chassis, a Check Engine light basically means that the engine computer has signaled something. Just what that may be should be covered in the engine and chassis owner manual that should have come with the coach. It probably just says to read out the code, though. That means getting a code reader and finding the diagnostic plug, or having a shop do that for you.

I'm not aware of any diagnostic "switch", but there is probably a plug under the dash somewhere to connect a diagnostic code reader. If Tiffin told you there is an actual switch of some sort, call Tiffin Customer service and ask about it. Or check your owner manual.
 

ChasA

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You should have a chassis (Freightliner) manual. In it will be a section on using the driver info screen. One of the things you can do is retrieve engine codes.  But then you'll  need to find out what they mean. Do as Gary says and call 1-800-FTL-HELP.  They will be able to walk you through getting the code and then tell you what it means and how to proceed. When you call, be sitting in the driver's seat and have your key and the last 6 digits of your VIN. This SERVICE is available any time,  any day of the year.
 

SpencerPJ

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I think everyone should own and know how to use an OBDII reader.  You can pick them up for $30 at auto store, or Amazon, you plug them into a plug under dash, it reads out a number.  You hop on Google, and it tells you what is causing the code.  (Places like Autozone do this for NO-Charge as well)

It just keeps you educated and your mechanic honest.  Sometimes a code can mean a loose gas cap, what would your mechanic tell you? 

I sometimes get the feeling, that especially the elderly and those with a motorhome, especially out of state, have a label on them that others take advantage of, and if you have one of these simple readers, just might help you display a tad of knowledge when you go to the shop.

Here is a link to a simple reader, there are more sophisticated ones for sure.  They even have them that you plug in, leave plugged in, and use an app on your phone.  https://www.amazon.com/OBD2-Scanner-OBDII-Code-Reader/dp/B0743X5WV8/ref=sr_1_12?s=automotive&ie=UTF8&qid=1531311604&sr=1-12&keywords=obd+reader

Sorry if I hijacked the thread, maybe the OP has a system onboard to do this, but hoping others read the thread and consider owning a little tool like this.
 

JD Sharp

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Ferndale, WA
Thanks all, found answer on another forum. The Allegro Red has built into Driver Display Unit a diagnostic screen with captured fault codes.
 

Kevin Means

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I agree with you Spencerpj, but Freightliner diesel coaches don't use OBDII. They have a different diagnostic port, and a different diagnostic system that's used in large trucks. For the OP... our Freightliner Info Center will display any fault codes that are thrown by pressing and holding the 4 way switch on the control panel for a few seconds, then navigating to the maintenance menu where the codes are stored. It involves some button-pushing, but it's not hard. I wrote the steps down, so if you'd like me to get them for you, just ask and I'll dig them out. Freightliner provided them to me.

Kev
 

JD Sharp

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Ferndale, WA
Thanks, I found the diagnostic screen and the fault codes, and called Freightliner. They were very helpful with what faults were are suggested taking to service center.
FYI I also got a low voltage warning after starting engine (note: in storage and not hooked up to power), so I checked chassis batteries. The were originals from June 2011, time to replace. After installation of new batteries and running engine to top off, much to my surprise, check engine light went out and all faults were erased.
So just because there is enough power to start with, these newer diesels obviously do not like anything under 12 volts when running.
 

Kevin Means

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Glad it's resolved. Since they were 2011 batteries, it probably was a good idea to replace them. Keep in mind, however, that the air intake heater on a diesel engine draws a lot of current when the engine is first started, and it's not terribly unusual to get a low voltage warning... especially if the batteries have been discharging while the coach was in storage.

While idling, after first starting the engine, the alternator is working pretty hard for a short period of time to power everything. Watch your voltage gauge when you first start the engine. The volts go waaaay down when the air intake heater kicks on, and then returns to normal when it kicks off. We can't even operate our two larger slides until the air intake heater kicks off, or we'll get a low voltage error on the slide control.

Kev
 
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