272bajadriver

iTrader: (1)

I have a 2001 GMC Sierra 2500 8.1 with allison transmission at about 120k. Truck has been flawless with me. It's not my daily driver just my tow vehicle. Today when I went to turn it on the Service Engine Soon light turned on. I went to the auto parts store and they hooked up their scanner to it and came back with code numbers P0847 and P0700 which both I believe have to do with the Transmission Control Module. I notice there was water dripping out of the end of the catalyc converter, didn't know if it was possibly related? When I drove the truck to the auto parts store it ran great as always. No gear shift issues or anything like that. Can someone who is more familier on this shed some light on how to go about fixing this issue? Thanks

Rwbrew3

[QUOTE=272bajadriver;3822602]I have a 2001 GMC Sierra 2500 8.1 with allison transmission at about 120k. Truck has been flawless with me. It's not my daily driver just my tow vehicle. Today when I went to turn it on the Service Engine Soon light turned on. I went to the auto parts store and they hooked up their scanner to it and came back with code numbers P0847 and P0700 which both I believe have to do with the Transmission Control Module. I notice there was water dripping out of the end of the catalyc converter, didn't know if it was possibly related? When I drove the truck to the auto parts store it ran great as always. No gear shift issues or anything like that. Can someone who is more familier on this shed some light on how to go about fixing this issue? Thanks
*


6.6 GMC 2500 code P0847
P0847 code Transmission Fluid Pressure Sensor/Switch "B" Circuit Low.

The pressure switch is the "Tin" looking part that is attached to the valvebody. Not expensive, and you don't have to remove the valve body.

Rick

Rwbrew3

The P0700 code sets when there are other transmission related codes present

Start with the p0847 fix ( above ) then clear codes and see if returns...

Rick

272bajadriver

iTrader: (1)

[QUOTE=Rwbrew3;3822605]I see you have on there 6.6 GMC I have the 8.1L 496 is the code still the same?

Rwbrew3

Sorry about that, no, not the same.. You may want to call the dealer and see about reprogramming the transmission control module ( tcm ) with the new service calibration, and have your PCM reflashed, I believe this is in there bulletin as a Fix for this problem, may even be covered, I'll try and find info and post for you .

Rick

FIXX

iTrader: (2)

your slipping from 4th to fifth gear and you may not have a fifth gear with the po 700 now..you usually have to clear the code,,this may have set if you have a tuner in the vehicle and or if you were towing with out using the tow haul mode..basicly the trans is slipping in higher gears..if your governor pressure is sticking or the valve is leaking then it could be the problem..like mentioned try changing it,its the biggest solenoid in the valve body..change your filter also,,try to reuse your gasket or like i would do get a new one from the dealer for 40 bucks,,they are reusable..
if problem is still their then get ahold of Arcticfriends he ie a trans guru..

Rwbrew3

Document ID# 880188
2002 Chevrolet Chevy K Silverado - 4WD

http://service.gm.com/engif/000/999/999/999999995.gif Subject:Harsh or Delayed 2-1 Downshift, Neutral Feel at a Stop, Shift Busyness, DTCs P0708, P0847, P0872, P0875, P1711, P1713 (Reprogram TCM) #02-07-30-020 - (04/22/2002)


Models:2001-02 Chevrolet and GMC C/K 2500/3500 (3/4 and 1 Ton) Series Pickup Models (Silverado and Sierra)
with Allison® Series 1000 Automatic Transmission (RPO M74)



<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=880188&pubid=271#ss1-880188">Condition

Some customers may comment on a harsh or delayed 2-1 downshift, a neutral feel at a stop or shift busyness (excessive shifting). Upon investigation, the technician may also find one or more of the following DTCs set:
• P0708
• P0847
• P0872
• P0875
• P1711
• P1713
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=880188&pubid=271#ss2-880188">Correction

Reprogram the Transmission Control Module (TCM) with the new service calibrations which were available from Techline starting March 24, 2002 on the TIS2000 version 3.5 or later. These calibrations are electronic calibrations and are NOT available from GMSPO.
These new calibrations will address the following conditions:
2001
2002
Delayed 2-1 downshift at a stop
2-1 downshift quality concerns
Flare & bump on low speed coast-down and throttle reapply
Cold shift quality concerns
2-1 closed throttle neutral feel
*Shift busyness
Harsh 2-1 downshift
DTC P0708, P0847, P0872, P0875, P1711, P1713
Shift busyness
2-1 closed throttle neutral feel

*Important: 2002 Vehicles with 8.1L Engine --
If the concern is shift busyness, the PCM must also be reflashed to gain maximum benefit from the new TCM service calibration. This calibration was available from Techline starting March 10, 2002 on the TIS2000 version 3.0 or later. If the concern is not shift busyness, this step is not required.


This additional step is not required on vehicles with a 6.6L diesel engine (RPO LB7) or 2001 vehicles with an 8.1L engine (RPO L18).


<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=880188&pubid=271#ss3-880188">Warranty Information

For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
K5364
Module, Transmission Control - Reprogram
0.4 hr
J6355
Powertrain Controller -- Reprogram
0.4 hr


GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
http://service.gm.com/engif/000/999/999/999999994.gif WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

© Copyright General Motors Corporation. All Rights Reserved.
Does this help????

Rwbrew3

Found that info on line, good luck..

Rick

272bajadriver

iTrader: (1)

Forgot to mention the sierra 2500 hd is completely stock. I never use the tow/haul mode do you guys?

FIXX

iTrader: (2)

thats why its their,,makes a firm shift..