ABS / Brake Bleed issue with 2015 Spark EV

[SmokeyPete]

Hello fellow Spark EV owners,

My odometer is at 66k and I wanted to be proactive and perform at brake flush on my 2015 Spark EV. In 2018 when I originally purchased the car from Carvana at 16k miles rather than pay $100 for a pre-inspection I spent a little more money on a VX Diag Nano for GM from Amazon.com and ran their copy of GDS2 to check overall car health (mainly battery voltage readings).

A year later in 2019 I accidentally popped out the rear right brake caliper while checking the car for an emergency brake cable/module issue and lost a bit of fluid but easily reassembled the disc brake and did a quick bleed to make up for the lost fluid.

It's now 2022 and I have been reading up that one should do a complete brake bleed every few years. I attempted to perform an old fashioned two person brake bleed with the complaining girlfriend at the pedal and me at the four bleeder valves as well as watching the master cylinder level. After my first attempt I ended up with the MIL going on as well as a Stabilitrak error as well as a C12E9 code. My girlfriend may have misinterpreted (or just ignored) some of my instructions and pumped the brake all the way to the floor once or twice but I'm hoping that since my fluid was relatively clean that no contaminants could have wrecked anything in the brake cylinder?!

I googled around for a solution and saw PIC5423C about having to use a pressure-bleeder for 2011-2014 Volt and 2014 ELR and 2014 Spark EV (I assume 2015 too) at 30 PSI Minimum so I picked up the Motive Pressure Bleeder. My friend has access to Alldata and provided me with both the "Hydraulic Brake System Bleeding (Pressure) as well as the Antilock Brake System Automated Bleed System instructions.

https://static.nhtsa.gov/odi/tsbs/2014/MC-10111843-9999.pdf

At this point I have probably run the Hydraulic Brake Bleeding 3-4 times and the ABS Automated bleed at least twice. I'll admit it's kind of hard to keep the Motive pressure at a constant 30 PSI since any bleeding drops the pressure down 5-10 PSI pretty quickly. I no longer have an active MIL but the first inch to 1-1/2 inches of brake pedal feel is mushy. Since the GM parts involved seem to be quite pricey and not available on RockAuto I have yet to drive my car out of my back yard in fear of really damaging something expensive. My stored codes codes are: C12E0, C12E9, C12FE

I am thinking that I should continue to use the XVDIAG VCX Nano with the GDS2 unit in hopes that repeated uses of either the "ABS Automated Bleed" or the "Hydraulic Brake System Bleeding (Pressure)" resolves the issue with mushy brake feel.

Does anyone know if I should keep running both procedures or if I should concentrate on just one? Am I even on the right track or is a different procedure or approach in order? Being in Massachusetts I am concerned that most mechanics will be as unfamiliar with the specifics of the Spark EV as I am.

Thanks,

 

[MINITSLA]

Smokey, I just ran into this exact same problem after replacing both rear calipers (the left one was sticking), and attempting a manual bleed. Every since then I've had the same codes as you.

I took the car to the Chevy dealer in Dartmouth, Mass., where they said it needed a new brake booster or control module, but they didn't know which. So I ordered a used assembly from California and replaced it myself.

This time, instead of doing a manual bleed, I too used a Motive pressure bleeder, but when I pumped it up to 30 psi, the fluid shot out of a port at the bottom of the reservoir (pointing to it in the pic). With my tail between my legs I brought the car to the Chevy dealer in Bourne (where it is now) hoping they can figure this out. Were you able to resolve your issues?

 

[SmokeyPete]

Yes, I did but I wrapped the reservoir and cap with some duct tape and prayed to St Spark before I attempted the process. It certainly was nerve racking.
Sorry you got wet. I guess you can only expect so much from a affordable motive pressure bleeder. No shame going to a dealership as long as they are honest folks.

 

[MINITSLA]

Yes, I did but I wrapped the reservoir and cap with some duct tape and prayed to St Spark before I attempted the process. It certainly was nerve racking.
Sorry you got wet. I guess you can only expect so much from a affordable motive pressure bleeder. No shame going to a dealership as long as they are honest folks.

So you used duct tape and a Motive pressure bleeder, and you were able to get rid of the codes? Do you remember how many psi you used with the bleeder? Did you wait 15 seconds between pedal pumps per the manual? Was the car turned on when you did it?