Road Trip Interruption
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Instructor
Joined: May 2021
Posts: 160
Likes: 182
From: Oracle, AZ
Road Trip Interruption
About 1,500 miles into our road trip from Tucson to places scattered all over the U.S.A, we went to the Kentucky Derby Museum. My wife loved it, I only sorta liked it.
We get in the car (2022 HTC) to leave the parking lot, started it, and pulled the R button to back out of our spot. I got "Service Transmission" and the dreaded Check Engine light on the dash. The car could not be put into gear, and driven. Further, I could not put it in Park, or Neutra or Drivel. I hit the OnStar button and spoke with them. I couldn't turn the ignition off, tho I could stop the motor. OnStar sent me a diagnostic report, which included a code P1789.
5 hours later, the car was towed to a local dealer (Bob Hook Chevrolet), who was closed. It was 9 PM. Since the dealer was closed, the car sat in the dealer lot with lights on, dash lit and the battery ran dead by the next morning.
Stranded in Louisville, we found stuff to do. There are some pretty great restaurants in that city...
When I called the dealer the next day, they said they had charged the battery and had driven the car into the service stall. This is interesting news.
When we visited the dealer later, the service tech working on the car had it hooked up to a computer and was pulling codes. He did not have all the codes sent to me by OnStar, particularly the P1789 diagnostic code. I provided him with my codes. The P1789 code had been cleared by the dead battery. Either this code being cleared, or another code being cleared, allowed him to drive the car.
So, if I had disconnected the battery myself, in the parking lot of the Kentucky Derby Museum, I could have driven the car...
The dealer had one Transmission expert and he was in Transmission school till the following week. Sigh.
While waiting for some resolution, and hoping I didn't need a new Transmission, I google searched. I found stuff, including a report from the NHTSA, which GM had filed with them. This report describes exactly what we experienced.
3 days later, I get a call from the dealer. The car was fixed. The Service writer said they had re-flashed the ECM and TCM after finding the K71 and K20 modules had out of date software. Note that I had done all the OTA updates. Presumably these K71 and K20 updates can only be done at a dealer, and the dealer has to know they're needed. I asked for, and received, a copy of the TSBs they referenced when repairing the car. There were a number of TSBs. Perhaps the most interesting ones are: 6082812, 5847343, 5847340
The battery was NOT replaced, though I told them it should be since it was run all the way dry. They tested it and found it to be OK. Hmmmm.
GM Roadside Assistance has been helpful. We spoke with them a number of times, keeping them up to date with our status. They reminded us and reminded us to KEEP YOUR RECEIPTS! We did, and will be filing a claim.
We finished our 6,800 miles with no further problems.
We get in the car (2022 HTC) to leave the parking lot, started it, and pulled the R button to back out of our spot. I got "Service Transmission" and the dreaded Check Engine light on the dash. The car could not be put into gear, and driven. Further, I could not put it in Park, or Neutra or Drivel. I hit the OnStar button and spoke with them. I couldn't turn the ignition off, tho I could stop the motor. OnStar sent me a diagnostic report, which included a code P1789.
5 hours later, the car was towed to a local dealer (Bob Hook Chevrolet), who was closed. It was 9 PM. Since the dealer was closed, the car sat in the dealer lot with lights on, dash lit and the battery ran dead by the next morning.
Stranded in Louisville, we found stuff to do. There are some pretty great restaurants in that city...
When I called the dealer the next day, they said they had charged the battery and had driven the car into the service stall. This is interesting news.
When we visited the dealer later, the service tech working on the car had it hooked up to a computer and was pulling codes. He did not have all the codes sent to me by OnStar, particularly the P1789 diagnostic code. I provided him with my codes. The P1789 code had been cleared by the dead battery. Either this code being cleared, or another code being cleared, allowed him to drive the car.
So, if I had disconnected the battery myself, in the parking lot of the Kentucky Derby Museum, I could have driven the car...
The dealer had one Transmission expert and he was in Transmission school till the following week. Sigh.
While waiting for some resolution, and hoping I didn't need a new Transmission, I google searched. I found stuff, including a report from the NHTSA, which GM had filed with them. This report describes exactly what we experienced.
3 days later, I get a call from the dealer. The car was fixed. The Service writer said they had re-flashed the ECM and TCM after finding the K71 and K20 modules had out of date software. Note that I had done all the OTA updates. Presumably these K71 and K20 updates can only be done at a dealer, and the dealer has to know they're needed. I asked for, and received, a copy of the TSBs they referenced when repairing the car. There were a number of TSBs. Perhaps the most interesting ones are: 6082812, 5847343, 5847340
The battery was NOT replaced, though I told them it should be since it was run all the way dry. They tested it and found it to be OK. Hmmmm.
GM Roadside Assistance has been helpful. We spoke with them a number of times, keeping them up to date with our status. They reminded us and reminded us to KEEP YOUR RECEIPTS! We did, and will be filing a claim.
We finished our 6,800 miles with no further problems.
Pro
Joined: Sep 2022
Posts: 592
Likes: 654
About 1,500 miles into our road trip from Tucson to places scattered all over the U.S.A, we went to the Kentucky Derby Museum. My wife loved it, I only sorta liked it.
We get in the car (2022 HTC) to leave the parking lot, started it, and pulled the R button to back out of our spot. I got "Service Transmission" and the dreaded Check Engine light on the dash. The car could not be put into gear, and driven. Further, I could not put it in Park, or Neutra or Drivel. I hit the OnStar button and spoke with them. I couldn't turn the ignition off, tho I could stop the motor. OnStar sent me a diagnostic report, which included a code P1789.
5 hours later, the car was towed to a local dealer (Bob Hook Chevrolet), who was closed. It was 9 PM. Since the dealer was closed, the car sat in the dealer lot with lights on, dash lit and the battery ran dead by the next morning.
Stranded in Louisville, we found stuff to do. There are some pretty great restaurants in that city...
When I called the dealer the next day, they said they had charged the battery and had driven the car into the service stall. This is interesting news.
When we visited the dealer later, the service tech working on the car had it hooked up to a computer and was pulling codes. He did not have all the codes sent to me by OnStar, particularly the P1789 diagnostic code. I provided him with my codes. The P1789 code had been cleared by the dead battery. Either this code being cleared, or another code being cleared, allowed him to drive the car.
So, if I had disconnected the battery myself, in the parking lot of the Kentucky Derby Museum, I could have driven the car...
The dealer had one Transmission expert and he was in Transmission school till the following week. Sigh.
While waiting for some resolution, and hoping I didn't need a new Transmission, I google searched. I found stuff, including a report from the NHTSA, which GM had filed with them. This report describes exactly what we experienced.
3 days later, I get a call from the dealer. The car was fixed. The Service writer said they had re-flashed the ECM and TCM after finding the K71 and K20 modules had out of date software. Note that I had done all the OTA updates. Presumably these K71 and K20 updates can only be done at a dealer, and the dealer has to know they're needed. I asked for, and received, a copy of the TSBs they referenced when repairing the car. There were a number of TSBs. Perhaps the most interesting ones are: 6082812, 5847343, 5847340
The battery was NOT replaced, though I told them it should be since it was run all the way dry. They tested it and found it to be OK. Hmmmm.
GM Roadside Assistance has been helpful. We spoke with them a number of times, keeping them up to date with our status. They reminded us and reminded us to KEEP YOUR RECEIPTS! We did, and will be filing a claim.
We finished our 6,800 miles with no further problems.
We get in the car (2022 HTC) to leave the parking lot, started it, and pulled the R button to back out of our spot. I got "Service Transmission" and the dreaded Check Engine light on the dash. The car could not be put into gear, and driven. Further, I could not put it in Park, or Neutra or Drivel. I hit the OnStar button and spoke with them. I couldn't turn the ignition off, tho I could stop the motor. OnStar sent me a diagnostic report, which included a code P1789.
5 hours later, the car was towed to a local dealer (Bob Hook Chevrolet), who was closed. It was 9 PM. Since the dealer was closed, the car sat in the dealer lot with lights on, dash lit and the battery ran dead by the next morning.
Stranded in Louisville, we found stuff to do. There are some pretty great restaurants in that city...
When I called the dealer the next day, they said they had charged the battery and had driven the car into the service stall. This is interesting news.
When we visited the dealer later, the service tech working on the car had it hooked up to a computer and was pulling codes. He did not have all the codes sent to me by OnStar, particularly the P1789 diagnostic code. I provided him with my codes. The P1789 code had been cleared by the dead battery. Either this code being cleared, or another code being cleared, allowed him to drive the car.
So, if I had disconnected the battery myself, in the parking lot of the Kentucky Derby Museum, I could have driven the car...
The dealer had one Transmission expert and he was in Transmission school till the following week. Sigh.
While waiting for some resolution, and hoping I didn't need a new Transmission, I google searched. I found stuff, including a report from the NHTSA, which GM had filed with them. This report describes exactly what we experienced.
3 days later, I get a call from the dealer. The car was fixed. The Service writer said they had re-flashed the ECM and TCM after finding the K71 and K20 modules had out of date software. Note that I had done all the OTA updates. Presumably these K71 and K20 updates can only be done at a dealer, and the dealer has to know they're needed. I asked for, and received, a copy of the TSBs they referenced when repairing the car. There were a number of TSBs. Perhaps the most interesting ones are: 6082812, 5847343, 5847340
The battery was NOT replaced, though I told them it should be since it was run all the way dry. They tested it and found it to be OK. Hmmmm.
GM Roadside Assistance has been helpful. We spoke with them a number of times, keeping them up to date with our status. They reminded us and reminded us to KEEP YOUR RECEIPTS! We did, and will be filing a claim.
We finished our 6,800 miles with no further problems.
glad it worked out for ya, also batteries running dead do not mean they need to be replaced. just fwiw.
Drifting
Joined: Nov 2012
Posts: 1,670
Likes: 1,404
From: Central Ohio
Sorry this happened, but fortunately you had spare time and things to do nearby. So if you would’ve disconnected the battery and could drive as you suggested, could you continue on your journey until you got home and then get the updates? It seems like a lot of issues involve resetting the electronics by disconnecting the battery momentarily. I think it’s a good idea to have tools to do so in the car at all times. Amazing to me that a needed update can leave us stranded. I wonder the best way to avoid this?
Drifting
Joined: Mar 2018
Posts: 1,301
Likes: 928
From: Garden City New York
Excellent info on the battery disconnect to clear the ecu- Stuck on a road somewhere its worth a try. I know this is a forum on a car at 100k production volume but there seems to be quite a few issues to be wary of
Moderator
Joined: Dec 2002
Posts: 40,887
Likes: 4,342
From: Lakewood Ranch, FL
Glad you are back on the road. The battery is more than likely OK but many more dead batteries and it will likely stay dead. Keeping it on a maintainer whenever possible will prolong the battery life in my experience.
