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Towards the end of a long drive tonight I got on the car hard in 2nd to pass a slow car on a fun road in a place I absolutely shouldn't have passed.
I was instantly punished with a CEL. I called OnStar and they said P0128. I googled it and was like hmm makes no sense. This code is from the future. It's the code I might get if I put in a lower thermostat which I had been considering doing. So now I was heading out for a trail run in my yellow short shorts and decided to call them back while getting a tiny little fvcking stick out of my sock. They said it's a P012B. Ahhhh this makes more sense. Maybe? I did a search of course but didn't see much on the code. Not sure if it matters but I get on the car that hard all the time. A few minutes before I did go through a very bouncy dirt road at Baja 500 speeds. The dust is still in the air I'm sure.
Its funny every time I'm about to say f it and tune the car, which isn't often, I find myself happy I didn't.
Anyone else ever get this code? Any suggestions to save me from a trip to the dealer?
Just drove a mile back home. Boost gauge seems to be acting weird. It seems to be on vacuum more often then it should be. At part throttle, enough to be getting boost usually, it's at 0. If I get on it hard it gets up to about 6, usually it hits about 12. At idle it's about -7.5. This is all based on the physical gauge I didn't feel like playing with the dash controller tonight. Performance wise I couldn't really play with the acceleration limits as with the X-pipe it would be a bad idea.
Just drove a mile back home. Boost gauge seems to be acting weird. It seems to be on vacuum more often then it should be. At part throttle, enough to be getting boost usually, it's at 0. If I get on it hard it gets up to about 6, usually it hits about 12. At idle it's about -7.5. This is all based on the physical gauge I didn't feel like playing with the dash controller tonight. Performance wise I couldn't really play with the acceleration limits as with the X-pipe it would be a bad idea.
Dropped it off at the dealer today and waited expecting to have to go home empty handed. After a couple hours they said they reset the code, checked the supercharger solenoid, drove it, light didn't come back on, all is well. I mentioned that the boost gauge seemed off. He said yes because when there is that CEL it will keep the wastegate open or whatever it's called. Hmm ok makes sense to my limited knowledge and I drove home. The light didn't come on but the boost gauge still isn't acting normally and the car, while still having a lot of power, feels a bit off. I was able to floor it in first from a stop without painting the road black which is something I haven't been able to do since the BMS filter install. Needless to say I'm going to bring it back after the holiday but I'd like to have some hard facts to point to other than "when you floor it it feels a little down on power and the boost gauge seems off" Any of you geniuses have any thoughts on the issue?
Attached is a photo of the boost gauge while cruising, off throttle, at speed and the other is in a full boost situation. Both of them seem more negative than I remember. I'd swear I was nearly touching the red in the past. Can anyone check and see what their looks like at idle, coasting at speed, and full boost?
Thanks!
Best,
Gene
p.s. yes I see the car is a little heat soaked but that's not the cause.
Last edited by phantasms; Jun 30, 2017 at 02:54 PM.
Assuming the boost gauge is relatively accurate (a BIG assumption, I know) it looks pretty normal. Maximum boost for the LT-4 is specified at 9.4 PSI so at most a shade above the third major hash mark above zero, it looks like your reading is just below that but watch it across the upper RPM range at heavy load/full throttle and see what it does (while a passenger watches that you aren't about to kill yourself and anything else).
On edit take a look at this video, your full throttle boost looks normal to me.
PS: You should also take into 'consideration' any recent induction changes too, if your using logic.
Second PS: Remember air temp/baro. pressure has an effect on the boost produced.
Last edited by C7/Z06 Man; Jul 1, 2017 at 12:41 AM.
So the tech reset the code, drove it and the light didn't come back on. When you pointed out that the boost gauge was not acting right, he said that was normal. In other words, they reset it, drove it, the light didn't come back on and they said it's all good. You then drove it and immediately knew it wasn't right. Yep, sounds like a typical trip to the dealer.
Assuming the boost gauge is relatively accurate (a BIG assumption, I know) it looks pretty normal. Maximum boost for the LT-4 is specified at 9.4 PSI so at most a shade above the third major hash mark above zero, it looks like your reading is just below that but watch it across the upper RPM range at heavy load/full throttle and see what it does (while a passenger watches that you aren't about to kill yourself and anything else).
On edit take a look at this video, your full throttle boost looks normal to me.
Agreed mine doesn't look far off from that but it used to go much higher. Maybe due to my mods, who knows.
Originally Posted by 2016 Z06
I think it's time for a ProCharger....
Obviously!
Originally Posted by onfire
How does the car drive with the code on. If the code bulb was burned out would you feel the change in power ?
After driving it some more it's definitely down on power. Mid and low range is down. Upstairs is not bad but not exactly right. I realize that's what's up with the boost gauge as well. It goes up when I hammer it but mid throttle it's still in vacuum and much less power. Also when I'm fully on it it doesn't sound quite right. More of a clanky exhaust sound...hard to say. Also, sometimes I hear what sounds like a slight whistle coming from under the hood. Maybe they installed a turbo.
Originally Posted by C7/Z06 Man
Per your pic 3000 rpm gets you approx. 8 pounds of boost, what does 6200+ get you. Try a lower gear to keep the speed down.
EDIT: Looked up P012B code and it looks like it could have something to do with the MAP sensor from the general description I read below.
PS: You should also take into 'consideration' any recent induction changes too, if your using logic.
Second PS: Remember air temp/baro. pressure has an effect on the boost produced.
All good points. Thank you as always!
Originally Posted by TRANS DAMM
My car has the corsa X plus extreme exhaust, halltech, and recently added a ported TB and car is running like crap since the ported TB. A ton of surging and jerky acceleration coming out of first. I got codes 102, and 121. I'm going to pull the TB off today and hope that's the issue. The car is not tuned. I haven't noticed and boost issues with my car though.
When I had the TB I have on now it was fine. I tried a different TB and my car started running like that. Went back to my old ported TB and it's perfect now. I'd definitely consider changing the PTB. Remember he said 95%...which is great...but there will be those with issues for some reason.
Originally Posted by onfire
Sounds like a bad TB or bad connection at the maf or tps. Who ported it ?
Originally Posted by 09Z06pj
So the tech reset the code, drove it and the light didn't come back on. When you pointed out that the boost gauge was not acting right, he said that was normal. In other words, they reset it, drove it, the light didn't come back on and they said it's all good. You then drove it and immediately knew it wasn't right. Yep, sounds like a typical trip to the dealer.
Exactly. Normally they're a pretty solid shop. They didn't have their regular guy on it. We'll see if it blows up before I bring it back on Friday.
Here's a video from a short drive. It's not normal, at least not for my car. I used to get right into the red and the needle was much less interested in running back to vacuum constantly.
Agreed mine doesn't look far off from that but it used to go much higher. Maybe due to my mods, who knows.
Here's a video from a short drive. It's not normal, at least not for my car. I used to get right into the red and the needle was much less interested in running back to vacuum constantly.
It looked fine to me. You really didn't even put it into boost range at 3K RPM. The one section where it wasn't creating boost looked fine too. There most likely wasn't a load on the SC enough to get boost.
I think your just really paying attention to it now after you threw the code.
P012B code tonight? Helps! :)
