Volt Guide: Repair Service High Voltage Charging System - 2012 Chevy Volt

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If you've seen this then you know all about the problems that come with this notice. I encountered this problem and found that most instances resulted in someone taking their vehicle to the dealer however since my Volt is not in warranty I wanted to fix this myself. I took it to the dealership initially before I had stated tearing into things to hopefully save some diagnostic time by getting their opinion. They told me the issue was a leaking battery coolant radiator and it needed to be replaced. I was quoted somewhere around $1400 to get this done. I told them I'd take the car home and consider my options, which was code for, "I'm not paying you this much money unless I have no other choice".

After searching online, every time I came across someone talking about doing this themselves, I found people saying how high tech everything was and how hard it is to bleed the coolant system and how you have to remove the entire front end of the vehicle, etc. But after removing the bumper cover (a few bolts and plastic rivets) I realized the battery coolant radiator is incredibly accessible and in front of the normal radiator, which means that accessing and replacing it would be very simple. So I went online and grabbed the part number to the radiator which is: 22765637 and I got the radiator for $173 shipped on ebay: https://www.ebay.com/itm/283302953535

Once the radiator is replaced, you need to bleed the coolant system which can be done with a software called GDS2, which can be ran using an OBD device called VCX Nano. I bought one of those off ebay for $108: https://ebay.com/itm/323655320408

After the bleeding process is done, you'll need to clear all the codes in the vehicle's modules including any Secured High Voltage Codes. In my case, there was another code which was set in the "Hybrid Powertrain Control Module 2" and refused to go away: P1FFF. There are many situations that will cause this code to appear, however it relates to an Isolation Hybrid/EV Battery Pack Isolation Test. If you go into this specific test inside the GDS2 menu, it was showing that my Isolation test status for the charging system and battery pack were passing, however down below it showed: "Hybrid/EV Battery Section Replacement" as "Not Successful". Leaving my car plugged in, clearing the code would for a brief instant show a green charging light and my car would honk however it would go right back to showing the Service High Voltage Charging System error on the display and in GDS2 the code would come right back and show up as current. It turns out this doesn't mean there is still an active issue, but in order to fully clear the code you have to re-program the Hybrid Powertrainj Control Module 2 entirely. Some dealers may refer to this as an update, but it is just reprogramming whatever OS or Calibration that module uses all over again. In order to do this programming, you'll need to subscribe to the AC Delco Technical Delivery System (TDS). Currently there is a 24 month access for a single vin for $40: