Allison Error Code P0700...???HELP NEEDED

[01_Duramax_Dually]

Can anyone shed some information about this error code,PO0700? I searched the forums and found nothing.
Man, I feel like a GM service Rep for my DMAX friends... :D A racing partner has a 02 2500HD DMAX/Allison. He called me late last night and said his truck is stuck at the dealer. He took it to the dealer as he was having the infamous "Will not hold high gear when towing". Then it down shifts to 3rd and will not come out that gear until you physically let off the gas but then you are going so slow you start the entire cycle over.

He took it to his dealer in AZ and they are not quite sure what to do. They have said the error code PO0700 was tagged.

All you Allison folks, can you describe that code and has there been any further corrections/upgrades for this situation?

He tows a 16K lb trailer.

[ 05-09-2002: Message edited by: 01_Duramax_Dually ]</p>

[mdrag]

01_Duramax_Doolie,

I checked www.obdii.com and nothing comes up for PO0700. I checked P0700 and came up with:

General Motors P0700 Transmission Control System

Don't know what it means though.

[01_Duramax_Dually]

MDrag,
Thanks....01_Duramax_Doolie....LMAO....just can't let the Big "Doolie" go.... :D I apologize but I cannot change...Something does not look right with that word..."Doolie".....

Thanks for the feedback, you are correct when I called him this morning it was error code P0700, not the extra "O"..sorry for that, it was his typo to me.

Anybody else have info?

[hoot]

I believe what BigAl said was that the TCM (Transmission Control Module) is an Allison exclusive computer and the ECM (Engine Control Module)is GM exclusive. The only (cost effective) way they could alert the driver of a Tranny fault was to tell the ECM. I believe 700 is the default for "tranny fault". When you get that, you then have to go into the TCM to retrieve the Allison specific fault code. Right SteveO?

[77TransAm]

hoot is correct. The P0700 code is a "TCM requested MIL" (malfunction indicator light, or SES). All it means is that the TCM has requested that the SES light be illuminated to indicate that a code has been set in the TCM. The real code is still in the TCM and should be able to be read with a scan tool.

[ChevysRus]

Basic question, did he replace the tranny filter at 5K???

Mine had a bad switch that worked a valve that was telling the tranny to go into 2 gears at the same time so it went into nothing (kind of like how I react when my wife and daughter are both telling me something at the same time) LOL

Anyway, the dealer should be able to get help from the Tech Line if they can't figure it out.

MudNerl has the same exact problem on another post and I think thier truck is going in on Monday to be fixed. Hopefully they will post the results and maybe a clue for your friend if the dealer can't get it sorted out by then.

Good luck

[MudNurI]

I do have this problem...and it is going in the shop tomorrow- to a different dealership, hopefully they are as helpful as they were on the phone.. I'll post my results tomorrow evening...

Brandy