Correct valve position for Corsa installation…

[Yo Nadz]

I’ll be installing the Corsa cat back exhaust next week and want to avoid the CEL valve issue I’ve been reading about. Rather than reviving an old thread I figured I’d make a new one in regards to it. Has anyone figured out the correct valve position for install? Disassemble with the valves open or closed? Install in the Corsa with the valves open or closed? How do I avoid this dreaded CEL?

Any insight is appreciated.

 

[Sully]

Put it into Tour mode, disconnect negative, install. If you throw a valve position code, perform a relearn. Very easy process. Regardless of which mode, if the computer senses an out of range variable it will require a relearn. Might as well just grab a Launch OBD bidirectional tool (unless you have one) and have just in case. If a shop is doing the install, they can do a relearn if need as well.

 

[rubberduck]

Are you suggesting the OP buy a $2000 tool?

 

[Sully]

Are you suggesting the OP buy a $2000 tool?

No, I'm suggesting the OP buy a $129 tool, which has been mentioned MANY times by myself, if he plans on installing the exhaust, to avoid any potential headaches.

 

[bl4ck_wng]

I have been trying to do an exhaust relearn but the tool says "not ready" under the learn function for exhaust valve relearn. The valves still function just fine, open and close as they should. Just cannot get rid of that damn CEL. Does anyone know what isn't ready? Or maybe if a dealer or tuning can override it and force readiness for the learn

 

[5VBW Nick]

Around the 1:50 mark they discuss and show the valve install. Doing mine very soon. Corsa also has instructions that go with the exhaust.

 

[Yo Nadz]

I have been trying to do an exhaust relearn but the tool says "not ready" under the learn function for exhaust valve relearn. The valves still function just fine, open and close as they should. Just cannot get rid of that damn CEL. Does anyone know what isn't ready? Or maybe if a dealer or tuning can override it and force readiness for the learn

This is exactly what I’m trying to avoid.

 

[Yo Nadz]

Around the 1:50 mark they discuss and show the valve install. Doing mine very soon. Corsa also has instructions that go with the exhaust.

Corsa’s instructions (at least the ones on their website) don’t mention anything about whether the valves should be open or closed, or what mode to disconnect the battery in. I did find these 2 instructions online, but they contradict each other.

 

[5VBW Nick]

Oh boy, not sure. I think as long as it goes back in the same way it came out the it should be ok?

Doing my install in a week or so.

 

[Yo Nadz]

Let me know how yours goes. I just got an email that my order has a 7 day lead time, so I’ll probably be installing closer to Easter.

 

[5VBW Nick]

Let me know how yours goes. I just got an email that my order has a 7 day lead time, so I’ll probably be installing closer to Easter.

I got that email, and it also said if you don't get your order shipped out within 31 days or something that you get a discount. That happened with mine and I emailed them and talk to someone on the phone and was never able to get that extra 7% discount or whatever it was that they were offering. I was a little pissed that they didn't follow up on their own policy, but at the same time I got some insane Black Friday deal and it ended up being $600 or $700 off the normal price.

 

[Yo Nadz]

Damn. I’m hoping it’s only 7 days. Anxious as hell. I also got a killer discount with there first responder thing (or at least I feel like I did. Still overpriced AF.). $2449 and no sales tax.

 

[Sully]

I have been trying to do an exhaust relearn but the tool says "not ready" under the learn function for exhaust valve relearn. The valves still function just fine, open and close as they should. Just cannot get rid of that damn CEL. Does anyone know what isn't ready? Or maybe if a dealer or tuning can override it and force readiness for the learn

Sounds like you may need a few more drive cycles (various driving, slow, hard, etc) for the adaptations to commit as there are a few sensors which must become ready for the relearn to become available. Assuming there's no mechanical issue with the actual valve itself. Were you in Service Mode before attempting the relearn?

Side note... doesn't seem many folks have read the service manual, there is no silver bullet to this issue as of yet, but new threads keep appearing. GM recommends performing "Exhaust Flow Control Valve Learn" (name of the document) procedure any time you service either the Fuel Pump PCM or the exhaust control valve actuator (This is also step 15/last step, of the actuator replacement procedure), which is the case for each time someone swaps over the actuators to the new exhaust...The relearn should be performed proactively before the first drive. The tension change caused by the removal of the actuator linkage from the actuator WILL CHANGE the values previously reported to the ECM. The values reported to the ECM from the actuator, are closely monitored and depended on by several other sensors which monitor ingress/egress of air/fuel within the system.

 

[5VBW Nick]

Sounds like you may need a few more drive cycles (various driving, slow, hard, etc) for the adaptations to commit as there are a few sensors which must become ready for the relearn to become available. Assuming there's no mechanical issue with the actual valve itself. Were you in Service Mode before attempting the relearn?

Side note... doesn't seem many folks have read the service manual, there is no silver bullet to this issue as of yet, but new threads keep appearing. GM recommends performing "Exhaust Flow Control Valve Learn" (name of the document) procedure any time you service either the Fuel Pump PCM or the exhaust control valve actuator (This is also step 15/last step, of the actuator replacement procedure), which is the case for each time someone swaps over the actuators to the new exhaust...The relearn should be performed proactively before the first drive. The tension change of the removal of the actuator linkage from the actuator WILL CHANGE the values previously reported to the ECM. The values reported to the ECM from the actuator, are closely monitored and depended on by several other sensors which monitor ingress/egress of air/fuel within the system.

So it sounds like before doing the install it might be a good idea to have one of those cheap scan tools that someone posted earlier in this thread?

 

[bl4ck_wng]

Sounds like you may need a few more drive cycles (various driving, slow, hard, etc) for the adaptations to commit as there are a few sensors which must become ready for the relearn to become available. Assuming there's no mechanical issue with the actual valve itself. Were you in Service Mode before attempting the relearn?

Side note... doesn't seem many folks have read the service manual, there is no silver bullet to this issue as of yet, but new threads keep appearing. GM recommends performing "Exhaust Flow Control Valve Learn" (name of the document) procedure any time you service either the Fuel Pump PCM or the exhaust control valve actuator (This is also step 15/last step, of the actuator replacement procedure), which is the case for each time someone swaps over the actuators to the new exhaust...The relearn should be performed proactively before the first drive. The tension change of the removal of the actuator linkage from the actuator WILL CHANGE the values previously reported to the ECM. The values reported to the ECM from the actuator, are closely monitored and depended on by several other sensors which monitor ingress/egress of air/fuel within the system.

Good info here. Thank you, Sully

I am 85% sure that I was in the correct ignition/service mode, but will have to try again to confirm now that it is warmer outside.

Some additional info -- I was an early adopter with a prototype kit for the 4BW -- I installed my system last October and have driven it about 7k miles so far, with multiple daily key cycles (this is my dd now). Even went out to the quarter mile for Halloween 2024 when I first got my kit to test it out. On a side note: Sounds diabolical on full throttle, functions perfectly as modes change, burbles/pops are thunderous, and it sets off car alarms in the office parking garage on command. Personally just can't stand looking at a CEL and not knowing if it is the exhaust codes, or something more serious lurking.

To resolve this, I brought it back to the dealer (they didn't want to plug into the OBD port unless I paid some ridiculous $180 diagnostic plugin fee (yes, $180 just to hook up and read/pull codes), plus $xxx per hour for them to guess/diagnose) -- hard pass unless they could prove it would work or they had done it successfully for another customer before (I was their first customer to present this issue -- they seemed overwhelmed with my request). I respected their honesty, good on them for putting it out there that they had no idea what to do.


My next stop is to locate a reputable NJ-based shop that works on c8 vettes and have them take a look

 

[bl4ck_wng]

So it sounds like before doing the install it might be a good idea to have one of those cheap scan tools that someone posted earlier in this thread?

yes -- some guys on here report it works for them

I purchased a creader elite 2025 prior to install. no dice for me (sadly)

trying again later this week then will elevate to a local vette tuner

 

[Sully]

yes -- some guys on here report it works for them

I purchased a creader elite 2025 prior to install. no dice for me (sadly)

trying again later this week then will elevate to a local vette tuner

I didn't see you were a 4BW but I can't imagine the recommended procedures, by GM would be any different for your actuators or purpose behind it.

As for the Launch ready/not ready, the Launch manual does discuss these scenario, it aligns with what I mentioned above.



In the OBDII section of the scanner, you can drill down into what module/sensor from the system is not ready to help determine where things are.

(disclaimer: I have no affiliation or anything with the Launch scanners... I have Autels, Xtools, and the Launch units and found that the Launch was the cheapest, simplest tool one could grab to perform some basic bidirectional functions. YMMV. They also come with lifetime updates which is nice... wish my Autel did...)

 

[bl4ck_wng]

I didn't see you were a 4BW but I can't imagine the recommended procedures, by GM would be any different for your actuators or purpose behind it.

As for the Launch ready/not ready, the Launch manual does discuss these scenario, it aligns with what I mentioned above.

View attachment 29852

In the OBDII section of the scanner, you can drill down into what module/sensor from the system is not ready to help determine where things are.

(disclaimer: I have no affiliation or anything with the Launch scanners... I have Autels, Xtools, and the Launch units and found that the Launch was the cheapest, simplest tool one could grab to perform some basic bidirectional functions. YMMV. They also come with lifetime updates which is nice... wish my Autel did...)

thank you again -- looks like I have to do some reading and understanding before jumping back into the process.

 

[5VBW Nick]

Just ordered the Launch tool, be here Monday.

 

[Yo Nadz]

Just ordered the Launch tool, be here Monday.

Send it my way when you’re done.