This might be coincidental but we were up in Live Oak, FL on June 30 to have a look at a piece of property we're buying to see how it fared with the flooding from tropical storm Debbie. While trying to make our way to the property we tried several routes and got into water a couple feet (maybe a little more) deep. Shortly thereafter we got the CEL and so I fired up Torque to see what the problem was (I always leave the bluetooth OBD reader plugged in). I saw several codes but didn't note them at the time. We went on our way with several more stops during the day and made our way home that evening without any problems.
The next morning (Sunday, July 1) I went outside to move the truck in prep for washing and after cranking it ran for about 30 seconds and then shutdown. Subsequent attempts to crank were unsuccessful and it would just turn over but not fire. It seemed to be a fuel supply issue at first glance. I again fired up Torque and pulled these codes:
P025A - Fuel Pump Module Control Circuit/Open
U0073 - Control Module Communication Bus "A" Off
P069E - Fuel Pump Control Module Requested MIL Illumination
P0700 - Transmission Control System (MIL Request)
Since I was still under warranty (more about this shortly), I called AAA and had the truck hauled to my usual service dealer (Dimmitt in Clearwater). It took them until Tuesday morning to narrow it down to the FPCM (20759945), a $60 part that they wanted $600 to replace. They said it wasn't covered under the powertrain warranty and I naturally disagreed. They referred me to Cadillac factory support via telephone and after speaking to Cadillac they said that the part should be covered and that the changes to powertrain coverage didn't go into effect until the 2010 model year and that's what Dimmitt must have been using as a basis for not covering this under warranty. The very nice lady at Cadillac put me on hold while she contacted Dimmitt service and explained the situation to them. Even then, Dimmitt still argued against doing the work under warranty so Cadillac lady said she would let me go and wait until she could speak to Dimmitt service management to sort it out.
A couple hours later, I got a call from my service rep at Dimmitt saying that they would cover the work under warranty because they found out that this particular part was covered under the
emissions warranty and not the
powertrain warranty.
As of this writing, the part has been replaced, programmed, and all of the codes cleared. I asked them to drive it a couple of times to ensure that the P0700 didn't come back as a separate issue and will reply to this thread if that turns out to be something else.
While this might have been a coincidental event, my mind can't help but correlate this to fording water 2+ feet deep on the flooded streets in and around Live Oak. I don't want to believe that my truck is *that* fragile.
So, the codes are posted here for future searching along with some information that may help someone else deal with an obstinate dealer who refuses to service this under warranty.
Given how helpless these GMLAN issues can make a relatively handy person feel, I might start seeking a mid-70's 4WD for a truly reliable BOV that can be maintained with the skills passed to me by my father. It's fun to play with Torque via OBD and see real-time stats from the engine, including real-time MPG which has helped me lighten my foot, but once this gets into trouble territory the code reading only goes so far. Even if I had replaced the FPCM, I don't have the tools to program it nor to validate that it's correct. Ugh.