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Not sure what section this should even go in...lol

We picked up our current 09 Signature last Aug. After getting a few minor bugs worked out I started having issues that I have yet to be able to figure out, or even where to take the coach to have it looked at. This started last November after running from AZ to OK. Everything was fine when we shut down and sat for a couple weeks. When we started back up the trouble began and has not stopped.

When I drive the ATC, Check Engine, and Check Transmission lights come on, Sometimes they come on all at once, sometimes it will just be one of them, sometimes none. They will randomly blink in no specific order. Speed or RPM does not effect anything. Obviously when the ATC light is on I have no cruise control or engine brake. They just randomly blink on and off, stay on, stay off......who know what they will do. When they do this the transmission shift panel either goes blank (not showing gear or gear selection) or I get the two horizontal lines with the diagonal line through each. The couple times I have been able to pull the codes via the transmission selector it says low voltage.

I have checked every ground I can find, I have been under the coach and unplugged the trans ECM and checked it. I have checked everything I know to no avail.

I have the Chassis Multiplex system. Would this be an issue with that? Is it a possible ground that I can't find somewhere? Where do I take it to even start to troubleshoot, knowing the multiplex system is basically a dead horse in finding anyone that can do anything on to it or to diagnose it. I just need a starting point on trying to figure it out. When all of this is blinking and beeping nothing is effected other than the cruise and engine brake. No codes, no loss of power/speed. This tells me it is purely electrical/electronic in signaling and not true faults or issues.

Any help is vastly appreciated. We love the coach, but damn if this aint frustrating.

09 Signature with the chassis multiplex

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Brett, you might have a communication issue but more likely you are having fuel filters that are starting to plug.  When that happens, an early sign is the atc light comes on.  When the transmission computer detects that the engine is not generating the target power output, the trans will shut off the ATC system.  Try changing your diesel fuel filters.

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39 minutes ago, Frank McElroy said:

Brett, you might have a communication issue but more likely you are having fuel filters that are starting to plug.  When that happens, an early sign is the atc light comes on.  When the transmission computer detects that the engine is not generating the target power output, the trans will shut off the ATC system.  Try changing your diesel fuel filters.

Frank, would this hold true when the trans codes show low voltage? I am going to see if my code reader will pull codes fromt he engine ECM, but have not yet.

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No, if you are showing codes for low voltage it is a battery/cable not a fuel issue.  This is a multiplex coach and unfortunately, BOTH house and chassis batteries need to be charging when driving.  If both battery banks and not reading the same charging voltage, it's likely time to clean big boy.

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37 minutes ago, Frank McElroy said:

No, if you are showing codes for low voltage it is a battery/cable not a fuel issue.  This is a multiplex coach and unfortunately, BOTH house and chassis batteries need to be charging when driving.  If both battery banks and not reading the same charging voltage, it's likely time to clean big boy.

I have done that already using your video. I feel both sets of batts are charging fine. No reason to think they are not.  Only code I am able to pull right now is from the transmission shift pad, and it shows low voltage as the only code. Let me see if I can pull it and can give exactly what it says.

 

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Frank, here are the two codes on the trans shift pad.

D1 U 0103 - U0103 Loss of communication with the first switch gear ON. Remains in the selected broadcast, monitors signal a change of direction. Display goes off on 10 sec, then shows-/-/-

D2 P2793 - P2793 An error occurred while communicating with the switch gear ON. Ignores a PWM (pulse width modulation) signal via CANbus also lost, blocked the last selected direction

With that, I am not sure exactly what it tells me...lol I don't know if this also then triggers the ATC and check engine lights, or if one of those triggers this light. Then I don't know what would cause whatever triggers what. 

Probably should move this to the engine/trans forum.

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Understanding how these systems work together can sometimes help to diagnose the issue.  A lot of odd codes will show up if there is a fuel or electrical issue.

From your list of codes, especially one of low voltage points me in the direction of an electrical issue.

If when the check engine and ATC lights come on you are seeing charging at both the house and chassis batteries, that would tell you that your battery and charging systems and big boy are fine.  But, this doesn't eliminate a communication issue between the engine and trans modules.  On your coach, I believe that the engine ECM is powered by the chassis batteries but the trans ECM and dash gauges are powered by the house batteries.  Unfortunately, your dash only shows the chassis battery voltage and not the house battery voltage.  That's why it's important to know both the house and chassis battery voltages when you see the problem.  An intermittent big boy charging issue could easily cause this problem especially if running at night with the lights on or if recharging nearly dead house batteries without using the generator.

Since you are seeing a low battery voltage error at the trans readout, is there also a low voltage engine ECM code stored?  Such a code could be a bad voltage cable or ground at the engine or trans ecm.  It's important to see what codes are stored at the engine ECM.  If there are any engine to trans communication issues or the engine doesn't generate the expected amount of power, the trans will disable the ATC system and turn on the ATC fault light.

 

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sounds like a CAN bus failure.

Ok, what is ATC - automatic Temperature Control?

Anyway...all of the controllers can share a single CAN bus (network).  If one of the controller's isn't happy, it can spit out noise on the network that affects the other controllers.  So, disconnect fuses one at a time that feeds power to the various modules until the noise goes away and the majority of controllers are happy.

Further then isolate if it's a wiring issue to the controller or the controller itself.

You can check resistance to ensure the end points have their normal 60ohm resistance (120 when both ends are correct and plugged in).  If the CAN bus is shorted or open,  then split the bus in half and retest to determine which half is wrong.

If you don't have the tools (scan tool, oscilloscope, etc) or the experience, this can be a tricky diagnostic.

I just went through the same with my wife's Escalade...ended up the suspension controller had a hole rusted through that allowed water into the brain causing corrosion and which then didn't pass the bus messages to the next controller on the network.

Edited by DavidL
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8 hours ago, Brett63 said:

Not sure what section this should even go in...lol

We picked up our current 09 Signature last Aug. After getting a few minor bugs worked out I started having issues that I have yet to be able to figure out, or even where to take the coach to have it looked at. This started last November after running from AZ to OK. Everything was fine when we shut down and sat for a couple weeks. When we started back up the trouble began and has not stopped.

When I drive the ATC, Check Engine, and Check Transmission lights come on, Sometimes they come on all at once, sometimes it will just be one of them, sometimes none. They will randomly blink in no specific order. Speed or RPM does not effect anything. Obviously when the ATC light is on I have no cruise control or engine brake. They just randomly blink on and off, stay on, stay off......who know what they will do. When they do this the transmission shift panel either goes blank (not showing gear or gear selection) or I get the two horizontal lines with the diagonal line through each. The couple times I have been able to pull the codes via the transmission selector it says low voltage.

I have checked every ground I can find, I have been under the coach and unplugged the trans ECM and checked it. I have checked everything I know to no avail.

I have the Chassis Multiplex system. Would this be an issue with that? Is it a possible ground that I can't find somewhere? Where do I take it to even start to troubleshoot, knowing the multiplex system is basically a dead horse in finding anyone that can do anything on to it or to diagnose it. I just need a starting point on trying to figure it out. When all of this is blinking and beeping nothing is effected other than the cruise and engine brake. No codes, no loss of power/speed. This tells me it is purely electrical/electronic in signaling and not true faults or issues.

Any help is vastly appreciated. We love the coach, but damn if this aint frustrating.

09 Signature with the chassis multiplex

Does the speedometer stop working and does the trans act different shifting gears?

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Wow, you have one of the last Signature coaches Monaco produced.  How cool!

A little history.  In 2005 Monaco introduced the Intellitec coach (house) multiplex system.  This system uses multiplex modules located in the back closet to operate most of the house electrical.  Then in late 2008 and 2009, they introduced the Kongsberg chassis multiplex system.  This system multiplexes most of the chassis electrical systems.  

Other 2009 coach owners have had issues and found the Kongsberg system tough to troubleshoot.  

There are only a few places that can work on your chassis multiplex.  M & M RV Electronics, Jason.  Direct phone number is: 419 965-3014 and the main number is 419 965-2662.  Also the guys at Premium Coach Group in Gilbert AZ may be able to work on it as well as some of the original Monaco Techs in OR.   

Just a start, but when you disconnect any of the wire connectors, look for bad pins and clean both sides with DeOxit before reconnecting.  Also look for any bad grounds.  

https://www.irv2.com/forums/f115/cadet-software-for-monaco-multiplex-chassis-432603.html  

Best of luck!

Edited by vito.a
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If you want to get a good reading of all the engine and transmission data, invest in a VMSpc interface,  and with your laptop watch what is happening in real time. VMSpc "https://www.silverleafelectronics.com/node/5868"

Here's a screen shot of my laptop. The VMSpc is on the left and I run the last version of TOPO for navigation on the right. This screen is always on whenever the coach is moving.

1578068835_SilverLeafscreen.thumb.jpg.cbacd9421fd0788db0ec1198babf55f6.jpg

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On 6/7/2021 at 5:36 PM, vito.a said:

Wow, you have one of the last Signature coaches Monaco produced.  How cool!

A little history.  In 2005 Monaco introduced the Intellitec coach (house) multiplex system.  This system uses multiplex modules located in the back closet to operate most of the house electrical.  Then in late 2008 and 2009, they introduced the Kongsberg chassis multiplex system.  This system multiplexes most of the chassis electrical systems.  

Other 2009 coach owners have had issues and found the Kongsberg system tough to troubleshoot.  

There are only a few places that can work on your chassis multiplex.  M & M RV Electronics, Jason.  Direct phone number is: 419 965-3014 and the main number is 419 965-2662.  Also the guys at Premium Coach Group in Gilbert AZ may be able to work on it as well as some of the original Monaco Techs in OR.   

Just a start, but when you disconnect any of the wire connectors, look for bad pins and clean both sides with DeOxit before reconnecting.  Also look for any bad grounds.  

https://www.irv2.com/forums/f115/cadet-software-for-monaco-multiplex-chassis-432603.html  

Best of luck!

It would be cool to know how far from the last one I have. No idea how to figure that out though. Last 8 of my VIN are 91049124

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