Service rear axle, P0300 on my new ‘21 2ss 1le
 

Two weeks ago i flew up to SC and drove a 2ss 1le home 9hrs no issues. The car has 5100mi and was previously owned by GM themselves, and its a GM certified pre owned.

I did all the track prep and went to a track day Sunday, in the first session going around a 40mph left hander, the TC turned back on, service rear axle, loss of hp, sounded like it was down a few cylinders, CEL flashing, car shaking so i pulled in. Dreaded(from what I’ve read) P0300 code. Disconnected the battery for a minute, reconnected and all good, no more codes no more shaking, went for a test drive and everything was fine so i went out for the next session. Next session at the end of a 120mph straight when i lifted off the gas on a left kink it happened again, i noticed both laps i ran over the turn 1 curb. First session it happened 2 corners after the turn1 curb, second session it happened the second the left front hit the turn 1 curb. The track is homestead Miami and its part of the line to run over the curb w the left sides. I can verify exactly when the issue occurs because the PDR shows “PTM race” turn off.

Pulled back in the pits disconnected the battery and drove all the way home 2hrs 80-85mph no issues. Did 5 hard pulls with the car hot and no issues. Reinstalled the stock intake (car has a corsa axle back and cold air inductions intake) and took it to the dealer this morning. They called me and told me they couldn’t replicate any issue and “did a software update.” How would you guys feel about that? I get not much they can do with out a CEL present, but I’m just really concerned about this issue w my new to me 1le.

Some factors to note is the car did sit for 5 months between me buying it and Gm offering it for auction to their dealers. The car came from Michigan and i live in FL, any factor there? It happened both times on left turns, both times after hitting the curb on the track.

Also, there is a big fire next to the track http://https://www.local10.com/news/local/2021/04/30/large-brush-fire-uncontained-in-miami-dade-county/ a 2019 ss 1le and a C8 we were running with also had same on track issues as me within 10minutes of each other. all of us had very different codes tho. We all got gas 40+ miles away from each other on different days so we dont think it was bad gas. There was tons of ash in the air from that fire, could that be a factor?

PDR of incidents -
Session 1, hit curb turn 1, turn 3 PCM race turns off (issues start)
http://https://drive.google.com/file/d/1cu3WyJ8oTkGs3s5YGNaeQf-qlZszRIjO/view?usp=drivesdk

Session 2, notice PTM race shuts off as soon as the car hits the turn 1 curb
http://https://drive.google.com/file/d/190N8RukwZU_t-1hDchu-WPyIl9_nEMZy/view?usp=drivesdk

I would think if it was valve springs or a loose plug wire or something the battery reset wouldn’t have fixed it, but the curbs have me suspect now of something loose?

Any insight is very appreciated

Check the harness under the coolant res. On the frame next to the ex manifold

Does your cai have the fins in it next to the maf?

I will check that harness, and yes

What’s up w those fins?

Update - Got the car back from the dealer and they cant find anything wrong with it. Gonna try running with the stock intake at the track Friday and swap to the CAI after a session or so. I will keep updating on this issue

The fins are needed in you have a factory standard intake tune on it

Yeah my cold air inductions intake has the fins.

Im gonna bring both intakes to the track Friday. Run the stock one then hopefully if all goes well with that swap over the CAI. Maybe well see if that was my problem.

When I swapped the CAI from my red SS I just sold to the 1LE I did it in 1 piece, the filter was a bit pressed up against the airbox, I wonder if when the engine moves under load and g force on the track if it was pulling itself apart? No idea just really stumped on this issue so far. No MAF code, just P0300

Exactly why i got a 1ss with a clutch pack lsd. Less electrical problems. GL with a fix

This is a misfire issue, the misfire is known to cause the service rear axle message

but yeah man I sold my 2020 1ss for this 1le... my 1ss was a beast and could took track days with no issues lol

Oh man, why didnt you just add the le parts to the 1ss? Some zl1le coilovers, FE4 sway bars and 6 pot calipers

Curbing is a non issue. I aggressively use curbing and have not had issues. I assume the dealer checked the diff fluid level? Ok? Has it ever been changed(per service history?) as it’s known to be full of metallic after break in and will need changed before track duty.

Rear dif fluid was changed last week.. I don’t think there’s anything wrong with the rear dif tho… the misfire caused the service rear axle. Why would I be getting a misfire from curbing?

Im really wondering if it has anything to do with the car sitting for 5mo between GM owning it and me buying it. Battery? Idk. really stumped on this, It wont do it on street. why does it happen so quickly on track?