2002 Monaco Roadmaster Chassis/ Allison Transmission Issue

[kwl0525]

I have a 2003 Monaco Cayman (2002 chassis) and the Check Trans light recently came on, the Allison 2000MH trans (with manual shifter) won't shift into overdrive (5th), and the exhaust brake won't engage. I took it to Allison transmission and there is nothing wrong with the transmission or the TCM (trans control module).

Allison says the error code appears to be 'OEM' (i.e. from the chassis manufacturer), which they can't diagnose. So I need to get the coach to someone that can read/diagnose Monaco error codes.

I'm in Columbus Ohio and the nearest Monaco dealers are over 100 miles away. Every place I've tried to call locally has no clue... and I'd prefer not to have it towed that distance, and driving that distance at a max of 45 mpg isn't realistic.

I have a call into Allied Recreation Group (current owner of the new Monaco), but haven't heard back.

If anyone has any insight or thoughts I'd greatly appreciate the insight.... otherwise I have a useless unit.

Thanks,

Keith

[dickandlois]

Keith,

You might give Monaco Customer Service a call. 877-466-6226. 7:00 AM to 4:00 PM Pacific Time.

Ask if they can tell you of a way to read the code # or if you have a code number - what is it related to and how to address the problem.

With the TCM and the ECM talking to each other it could be a fuel issue that is placed the Engine in Limp mode!

Rich.

[kwl0525]

Rich:

Thanks for the info. Monaco/Allied Recreation Group called back and pointed me to a local repair shop that used to be an authorized warranty shop for Monaco. I've contact them and it goes in Tuesday (5/26) to see what they can find.

Keith

[Walt2137]

Keith remove the power from the Allison for 10 minutes and see if the reboot helps, I remember a 99 Dynasty that this cured a problem similar to yours when Allison failed to find the problem.

Remove everything from both post of the chassis battery to reboot.

Walt

[dickandlois]

Interesting Walt,

Never would have considered that the ECM or ATM would have a reboot cycle!!

Rich.

[kwl0525]

Walt:

Thanks for the information. Allison's findings were that the ECU is giving off a CAN Bus Error code (trouble code U2105). Since the shop Monaco pointed me to can't see me until next week, I will definitely try your suggestion tomorrow and I appreciate the info for future reference.

Keith

[dickandlois]

Keith, thanks for posting the Code number. I'm going to keep looking into possibilities. the one item that keeps coming up is

Key on and the TCM did not receive ECM messages for 1 second. Time Out Error. The item that creates this error frequently is the neutral safety switch. There is a new term used for the switch, but I can not remember what it is!

A defective Neutral safety switch or an adjustment issue with the switch, if its a mechanical style gear selector- generally does not allow the engine to start.

This error is generated by the Transmission TCM - With all the communications of the vehicle electronics talking on the Control Area network / Bus(Can) also referred to as the J-1939 circuit.

This is a link to the fault codes listed by Allison. Page 7 list your code.

http://www.equipementsdelfosse.com/data/otc/genisys/FAULTCODEBOOK.pdf

Hope the reset mentioned by Walt works for you.

Rich.

[Walt2137]

Rich,

I hope it helps Keith also as I have never done the reboot myself. This was a fix posted on the Monacoers board for one of the members 6 or 8 yrs ago that struggled with a issue similar to Keith's for a few months and was posting about the problem until a (his words) very smart Allison tec did the reboot and as far as I know his problem never came back.

Keith keep us in the loop.

Walt

[kwl0525]

Walt and Rich:

Unfortunately, the reboot didn't work. The error code being registered is not coming from the tranmission. I took the unit into another local service center yesterday (5/26) that Monaco suggested as they have experience working on Roadmaster chassis (per Monaco). Keeping my fingers crossed....

More to come...

Keith

[dickandlois]

Walt and Rich:

Unfortunately, the reboot didn't work. The error code being registered is not coming from the tranmission. I took the unit into another local service center yesterday (5/26) that Monaco suggested as they have experience working on Roadmaster chassis (per Monaco). Keeping my fingers crossed....

More to come...

Keith

Thanks for posting your updates Keith!

Interesting that Allison mentions the code in one of there diagnostic code lists for the 2000 series Transmission. There is no code listed that match for the ECM! The trick is to find all the different modules used for the coaches and finding what appears to be proprietary information when it comes to codes.

Now I need to see if the code is also mentioned for the MH3060 series.

I'm curious about learning more regarding to the Data Bus systems anyway.

From the information I have uncovered regarding the J1939 data bus, it has a maximum run length of 40 meters., there can be a number of branches around 3 ft.long and it has a 200 ohm termination resistance. That covers the mechanical potion well, but when one gets into the codes for the different modules - that is a real Pandora's Box !!!!!

Rich.

[dickandlois]

Keith, some additional notes regarding you error code(S) !

Note: the Data network uses low voltage pulses to transmit information.

•Bus is made up of two wires: CAN_H and CAN_L. Terminate with 120 Ohm resistors.

•Bus is differential. Voltage drop from CAN_H to CAN_L determines 0 or 1.

•Dominant bit(0): CAN_H=3.5V, CAN_L=1.5V

•Recessive bit(1): CAN_H=2.5V, CAN_L=2.5V

With a voltage this low and any contamination at the Connections between the data harness and modules - errant codes can be generated.

Have you or the service centers tried to hold down the Mode key for over 10 seconds to clear the error code(s) ? I highly recommend that you write down any and all codes before performing this operation !!!

Then one could see if the system operates properly and or how quickly it resets codes!

With the 2000 series transmission, there is the mechanical gear selector and it has a Reverse - Neutral Safety switch Assembly located right next to the gear selector.

Rich.

Mechanical issues.

TRANSMISSION WILL NOT SHIFT

TO FORWARD OR REVERSE (STAYS IN NEUTRAL)

Engine rpm too high

Reduce engine rpm (it may be necessary to reselect N (Neutral) also, and then D (Drive) or R (Reverse)

Low fluid level Add fluid to correct level (refer to Mechanic’s Tips, MT4007EN)

Throttle position sensor or linkage is not functioning properly

Refer to Mechanic’s Tips, MT4007EN

Faulty throttle signal from engine

Correct engine throttle signal, Shift selector is not functioning properly

Repair shift selector or adjust linkage

Speed sensor(s) not functioning properly

Repair or replace speed sensor(s) circuitry (refer to Section 6–3, SPEED SENSOR REPLACEMENT)

Mechanical failure toC5 clutch

Repair transmission Mechanical failure in transmission torque converter, shafts, or planetaries

Repair transmission Low main pressure

Repair transmission Faulty wiring in TCM Input / Output function circuits.

Correct circuit wiring

[kwl0525]

Rich:

Thanks for the addiitonal information. I'll pass it over to the shop. Thus far they have determined that the Allison components are fine (confirmed by Allison). However, there is an issue from the ECU over to the TCM. Monaco has supplied them the wiring schematics and they are in the process of working through the wiring harness.

Hopefully they can identify and resolve soon.. going through wiring harnesses is not a cheap endeavor!! As wonderful as motorhomes are/can be, they can be just as awful when it comes to something like this!!

Thanks,
Keith

[kwl0525]

Here is the final update on this issue. Problem ended up being severely corroded wires in the main wiring harness. One for the wiring connectors had to be replaced also. The wiring issue was preventing all signals needed from the ECU to get to the transmission control module (TCM). This prevented the transmission going into 5th (overdrive) and also prevent exhaust brake engagement.

Once the wiring and connector issues were addressed, no more Check Trans light and everything is back to normal.

Thanks for all the additional information, I'm sure it helped narrow this down, and I'm keeping for future reference.

Happy and safe travels!

Keith

[jleamont]

kwl0525, did the repair shop provide you with the location of the corrosion?

[dickandlois]

I think the compromised link was between the Engine ECM and the Transmission TCM. If and I'm going to if this one-the TCM module would be mounted no farther then 3 to 6 ft. from the main data link trunk line.

That would kind of put the TCM module location under the bed / engine access cover and most likely mounted on the outer surface of the bed support base by the coach builder.

This location would keep it away from all the other items, like air, fuel, Dash AC, fuel lines and filters plus a few more for electrical items.

There would be a link between the TCM and the Transmission and between the TCM and the ECM looking at throttle position an these two modules carry on a constant conversation regarding the gear the transmission is in - the current load and how much torque is needed and what gear its running in. The ECM then commands the engine to deliver more power by increasing fuel supplied by the injectors and how much turbo boost is needed at any given moment an it is done in factions of a second.

This location would keep it away from all the other items, like air lines, fuel pump, injector pump, Dash AC compressor lines, fuel lines and filters plus a few electrical circuits more for electrical items.

The ECM's Mount on the engine. The under the bed would keep the TCM module out of most of the wheel spray and dirt, but the twisted data cable would be exposed to an Environment very unfriendly to data connections where any corrosion and or oxidation would start to degrade signals.

Data works great until noise reaches a point where the data can no longer be filtered out from background noise.

Compare it to the new cell phones - when the signal drops to low enough level - the things hang up and they do it at the most inconvenient times.

Rich.

[kwl0525]

Rich:

You are correct. The issue was compromised wiring between the ECU and the TCM.

On my coach the TCM is actually mounted to the roof of the rear-most cargo bay on the passenger side (on the inside of the cargo bay). I haven't been able to get underneath the coach to see exactly which wiring harness and connector plug had to be replaced. I plan to do that this weekend.

I do know that behind the cargo bay with the TCM, there are a number wiring bundles, some of which go to the trasmission and some to the Engine, so I'm certain the issue was in that area.

Keith