P1825 Internal mode switch: value out of range

[harristw]

have an 07 denali.....so the wife mentioned a while back that she was driving and then all of a sudden the check engine light came on, service stabilitrak came on, parking assist off, and the little indicator bar under the gear icon disappeared. by the time she got home the lights went out and was back to normal. The check engine light came on once while i was driving but went away the next day. Today the same issue happened with the wife (note the common thread here ..) and the check engine light stayed on. This time she had to pull over because when she was at a stoplight and tried to start going again it would go above 20mph, kinda like it had a rev limiter. She pulled over turned it off, waited a couple of minutes and fired it back up with only the check engine light on, made it home just fine.

So..pulled the codes and its a P1825 Transmission internal mode switch: value out of range. P0700 generic transmission fault code.

Anyone with any insight as to what the P1825 means in english please let me know. I'm planning on taking it in to the gmc dealer tomorrow but im very good mechanically and dont care to get taken for $$$. If anyone has an assembly diagram or wiring diagram or anything that will help me find this internal mode switch I would really appreciate it.

Help!

[harristw]

Since no one seems to know about this error I figure I'd enlighten some of you..

Searched online and found an exploded diagram view of my transmission. The Internal mode switch basically just lets the systems know which gear its in. Its part of the control valve assembly.

Took it to the local GMC dealer and they said its an internal transmission issue and will be covered under the 5yr 100k powertrain warranty! I'm bringing it back in on Monday and they will have it for about 3 days.

[pmbey]

I have the same problem on my 07 Denali and I was told the internal mode switch was not covered by powertrain warranty.

[Jimmiee]

I have the same problem on my 07 Denali and I was told the internal mode switch was not covered by powertrain warranty.

The internal mode switch or pressure switch manifold is just one of many sensors on your transmission all of which are part of the powertrain and should be covered while under warranty. How many miles do you have on your truck?

[pmbey]

I have 77k miles on my truck. The dealer just called and said the internal mode switch was in but I need to confirm whether this is or is not covered under the 5?100k warranty. Thanks for your help.

[harristw]

hey PMBEY whats the latest? are they replacing it under warranty for you?