P0700 obd2 transmission code

JAVINDRA

Original poster
Member
May 27, 2018
71
brampton ontario canada
I am lately getting a p0700 obd2 code which is a ECM control module failure . When this happens my service engine light is on and the transmission goes into limp mode (low gear) . I can with my scanner clear the code and then all is good . I changed the tranny fluid it was nasty but I still got this situation about a week later. Please any info on this common gmc issue (mileage is about 100 k) would be appreciated
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
First time I've seen it but a Google search found me this site with good info.


Readers digest of possible causes:
  • Bad transmission control module (least possible IMHO)
  • Faulty shift solenoid
  • Low fluid
  • Short circuit
  • Bad valve body
 

Maverick6587

Member
Dec 16, 2018
730
Sterling Heights, Michigan
Did you remove the transmission oil pan with that fluid change, so that you could swap the transmission filter and clean the magnet attached to the pan?
 

JAVINDRA

Original poster
Member
May 27, 2018
71
brampton ontario canada
No I didn't remove the pan but the fluid was black but I have since done a complete scan and it looks like the valve body is all bunged up alot of sensor errors probably from the dirty oil the transmission shop recommended a tranny rebuild
 

Maverick6587

Member
Dec 16, 2018
730
Sterling Heights, Michigan
The fluid (originally) was black or a really dark red? Is the fluid bright red now after the flush or still really dark? I would think if it was that dark (originally) that your filter is dead/plugged with gunk at this point.

I would try another flush after removing the pan (depending on the current color of the transmission fluid), cleaning the pan and magnet very well, and replacing the oil filter, which just pulls down (sometimes with a little force). They're going to have to change the trans filter anyway. This way you may escape having to have it rebuilt, at least for right now.

This would give you time to save up for a junkyard replacement or just the money to have them rebuild it for you (if you don't already have that money ready).
 
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JAVINDRA

Original poster
Member
May 27, 2018
71
brampton ontario canada
Thanks for the reply the tranny shop said that he doesn't believe in power or back flushing the transmission but you are right that the filter is probably plugged but before I go further with the tranny I got to take care of Acadia's other major fault the timing chains
 

JAVINDRA

Original poster
Member
May 27, 2018
71
brampton ontario canada
First time I've seen it but a Google search found me this site with good info.


Readers digest of possible causes:
  • Bad transmission control module (least possible IMHO)
  • Faulty shift solenoid
  • Low fluid
  • Short circuit
  • Bad valve body
had them drop the pan and they said the valve body was in ruff shape so I am getting that rebuilt plus a new filter. The tranny shop said the valve body was badly corroded I have sent some pictures
 

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