"Shift To Park", Loss of Power - 2017 Volt

Traveling along the Ohio Turnpike on a trip in my 2017 Volt, I had a “shift to park” message – twice. Bottom line, I was able to turn back and drive 100 miles home, switch cars and drive it to Serra Chevrolet the following Monday. After consulting with GM Technical Assistance, they replaced the “generator battery disconnector relay”, which is really an electronic module, and it required dropping the battery. They had the car back the following day.

For details of the incident, we had just left a 7-mile long construction zone with a split between the 2 sides of the highway, which meant concrete barriers on both sides with very little shoulder. The first indication of anything wrong was that the yellow blind spot detection light on the left mirror stayed on, unless I turned off the system from the settings – it could just be a coincidence, but it never recurred after that ignition cycle.

I was in the leftmost of 3 lanes passing semis at the end of the construction zone, when in rapid sequence, the air conditioning quit, there was a chime, the message said “shift to park”, and the car definitely lost much of its power. Not panicking, I got over two lanes around the semis and drove along the shoulder until I had a good, safe place to park. I called OnStar emergency road service, being resigned to waiting for a flat bed tow truck and going to a dealer. I had my dog in the back seat and all our stuff for the trip. While waiting, OnStar asked if I could shift to N for the tow. I started the Volt and the AC came on, without the shift to park message. I cancelled the road service, and we drove to the next rest area, where we needed a break anyway.

OnStar had given me 2 codes: P0A0C, which says lithium ion battery not performing as expected, and P1E00, engine electrical system, HPCM (hybrid powertrain control module?)

I talked to my service adviser, to see if he thought, given his knowledge, that it was reasonable for me to try to drive the 100 miles back home. The alternative was to leave the Volt with a small town Chevrolet-Buick dealer that might not have ever sold, serviced, or even seen a Volt. My adviser said to go on to our destination in Pittsburgh, that it was probably a fluke that wouldn’t recur. We got about 10 miles (just past an exit) when the shift to park message came up again as before – except I was riding the right lane just in case. My wife talked me into backing up to the exit, against my better judgement; we got off, turned around, and headed home. I put the car into “mountain mode”, thinking that perhaps with a greater state of charge on the battery, we could avoid future trouble. It likely was coincidence, but we drove home without any trouble.

We switched stuff to our Yukon XL – we were running quite late by then, and I wasn’t about to venture to Pittsburgh that night in our Bolt EV.

I drove to the dealer the following Monday with no problem, where they replaced the generator battery disconnector relay. I haven’t driven the Volt much since, but I will be driving it to Chicago soon, so we will see. I do have confidence in the repair though.

Unfortunately, I’ve seen too many of these types of reports on gm-volt, and even one report submitted to NHTSA. But even though the car lost power, it did not “stall”, and I was able to safely and calmly bring it across 2 lanes of semis and a bit down the road to a wide, safe spot on the shoulder. I sounds like the lithium-ion battery was disconnected and I was perhaps running on the direct coupling of the engine to the drive wheels.