whitesierraRT

I've had this 25A2 error off and on since I bought the truck in Feb. After one dead battery and several trips to the dealer I thought it was working ok. Not the case. The CEL didn't come back but code could not be deleted. When I took it in to have the shop delete the code, which they did, they said it had another recall concerning DEF. This time it had something to do with the DEF monitoring. My DEF gauge read one square down but after their fix it read 3/4 full (1500 miles). A few days later it read full again. I sent the service agent an email asking what to do next. No response so far. I will probably have to call or drop in for a response. BTW I never received an official DEF recall notice. No CEL at this time.

I now believe you are correct. Not driving much right now and not having the problems mentioned before. I know my truck sat for several months before I bought it with the AGM battery that died. Now that it's been replaced the problem seems to have gone away. If only I knew how to remove the old P25A2 code produced. My Autel code reader wont remove it.

Saw the recall the day after I bought the truck (2/18/2020). Took it in and the next day after I took it home my battery was dead. They put a new battery in. Not able to drive it much lately with all that is going on. "Mystery" - First thing in the morning I pop the hood and battery is at 65%. I leave the hood up and 30 minutes later I check the battery and it's at 100%. What's with that? At least I don't have a dead battery. The P25A2 code is still in the system and it won't delete with my code reader. No engine lite so maybe it's ok now?

Update - Truck seems to be functioning ok now. However when I check engine codes with my code reader the P25A2 still comes up even though the engine light is off. I tried to clear the code with my AUTEL reader without success. Any suggestions to clearing the code? Not going to the dealer right now because of the virus thing. 2020 Sierra 3 liter Duramax.

Same thing happened to me. New battery, bla bla. P25A2 code now.

I had the brake system recall the day after I took delivery 2/17/2020. A few days later lots of things went wrong including dead battery. After another trip to dealer still having some problems including the P25A2 code.

I'm having this exact same problem since purchase 4 weeks ago. Been back to dealer twice. I'll be back as soon as this virus thing settles down.

I'm receiving these exact same codes on a new 2020. Had it in the shop twice because the battery would drain. Problem seem to start right after the recall upgrade for brake problems when starting engine remotely for which I never did. After the dealer installed a new battery and supposedly found a lose wire I took it home. It's still giving the P25A2 code and draining battery. I'm now staying home because of Corona.