2018 Battery Energy Control Module (BECM)

What do you all think about replacing a battery module versus replacing the whole battery? I have a 2018 Volt, less than 19K miles. The engine light in my 2018 Volt flashed a couple times on October 12, 2021, so I took it to the shop the next day. On October 13, 2021, while driving it there, the car’s power was compromised - this message appear on the dash: “Propulsion Power Is Reduced”. The service rep at the dealership told me that “the main battery module is shorting out internally”. First he told me that my Volt’s battery needed to be replaced. The next day they told me that they would only be replacing a module in the battery.

Prior battery repair history:

• On May 11, 2021, the Powertrain Control Module 2 was updated in response to a notice I received from Chevrolet:
  “We have learned that your model year Chevrolet Volt may have a condition where it could gradually lose the ability to maintain voltage. If battery concerns are not addressed, over time the vehicle could enter a reduced propulsion mode while driving, or lose propulsion, or it may not start.” (What seemed to happen on October 13, 2021.)
• On November 6, 2020, the “Shift To Park” problem was repaired. It had happened frequently, and not since this repair.
• On December 20, 2019, the “Service Park Brake” problem was repaired. Happened a number of times, and not since this repair.

The car has been there for a week - no updates. They said it could take 2+ weeks.

Thanks, Charlie. That makes sense. I was uncomfortable bc I could not get a clear explanation from the shop at the dealership, and they gave conflicting information - even if they aen't weaseling, it sounds like they are. (They did try to weasel out of providing a rental car.)

I've asked numerous times for a work order with details - it's like I haven't said anything, Not looking forward to picking it up and repeating all my requests again. It's been patience-trying service at every step.

My 2018 Volt has been a great car overall. But as another poster wrote, this does not give me confidence about the long-term life and reliability. I have less than 19,000 miles on my Volt. (I bought my last car new - a 1994 Honda Accord that had for 23 years and was still reliable, operating and running really well when I bought the Volt. It was kind of ratty looking and I wanted a Hybrid but I felt like I was betraying a loyal pet when I gave it away. I don't think that's going to be happening with the Volt.)

Hello everyone. I own a 2018 volt purchased in 2017. I have had both the BECM fail as well as the shift to park switch. I am a licensed mechanic and was very frustrated with the service people in Canada. I pulled up 4 codes all refering to the BECM and the car failed to run. I reset the codes so I could drive the car to the dealer to get it fixed under warranty. When I told the dealer what codes I got and what happened he told me they were nuisance code and not to worry about it. I insisted he look at the report I had generated but he refused telling me I don't know what I am talking about. A day later the car dieded again , so again I reset it and drove it to the dealer. I was so frustrated I parked the car in the middle of the service entrance blocking all other cars and told him I'm not moving it, and he should move it ( since at that point it wouldn't start again). He then began to argue again with me that I don't know what I am talking about. So I just threw the key to him and walked out. An hour later they had someone else call me to tell me yes the BECM had failed and it was under warranty. I was lucky or perhaps because I made such a big deal out of there incompetence they had the parts and it fixed In 3 days. Shortly after the shift to park switch failed and I again took it to the dealer. This time it wasn't under warranty so I asked them how much to fix this. It was 2 hours labor and $150 for the entire shifter. I scratched my head and told them no thank you that is not going to happen. I'm not going to pay them $500 for something I can do myself. I removed the shifter ( only took me 10 minutes , not 2 hours ) and looked at the defective switch. The smallest switch I have seen. I did some modifications for a larger more robust switch ( something I use in industrial machinery good for millions of cycles ) and have not had a problem since.

The Battery energy control module BECM seems to be isolated to just the 2017-2018 model but the shift to park switch is a problem across alot of other models that share the same switch in the shifter. Like a money grab for GM. If you have the knowledge it's better to replace the switch rather than the shifter as it will most likely come back again