slow ride

It's weird how long this problem has been around and not been solved 100% I suggested to Ben only using one feedback circuit to feed the important ones that set this code that way they would match 100%, but I'm not sure if they rely on the same voltage levels or if input impedance would cause an issue. This would be more of an experiment and sort of a pain to do, but at some point the issue needs to be solved. I'd be curious to what more of the software guys thought about this issue and if it's fixable in code or if having a separate PCM and TCM make it harder.

Turbo-Geist

*Important Info*
This is the code I am getting:

DTC P1515 Control Module Throttle Actuator Position Performance

Circuit Description
The commanded throttle position (based on accelerator pedal position and possibly other limiting factors) is compared to the Actual throttle position. The 2 values should be within a calibrated range of each other. Both the PCM and the TAC module redundantly monitor the Commanded and Actual throttle position. This DTC sets if the PCM detects the problem.

So:
DTC sets if the "PCM detects the problem". The PCM and TAC module monitor Commanded and Actual Throttle Position, but the PCM sets the DTC. These two values need to be within a calibrated range.

Would the calibration parameters be in the PCM?

DRIVER456

Is it possible to make a stop for the blade on that TB so it doesn't go past the 100%/WOT? I see in one of your posts the the log is showing 107% I'm wondering if thats the problem,Also I remember reading on high boost cars the pressure was fluttering the blade or something like that or the pressure was forcing the blade opening to fast.I don't remember.Just throwing some idea's out there.

Turbo-Geist

Thanks. The 107 to 108% is the accelerator pedal position inside the car. The actual throttle blade never goes past 100%.

HPTuners recently gave the C6 world the functionality to change some things related to the throttle moving beyond the calibrated range. This is related to the fluttering or blade movement you mention. It has solved some of the problems with REP mode on the C6. I reached out to HPT and offered to do some beta testing to figure out how to fix it on the C5. They told me that I would have to figure it out for myself. Basically, if I know the address of the scalar, parameter, or table is in the binary code, I could add it via their new user defined parameters feature. By the way, it's $99 to add this functionality and there isn't a guarantee that it will work. I don't know anyone that has hacked the full C5 PCM and knows where the values are located, do you?

stevieturbo

If you cannot calibrate the fully open or closed positions of either the blade or the pedal....could you mechanically restrict the pedal so it never sees more than 100% and see if that changes anything ?

Presumably the error is because of the discrepancy between the two ?

Assuming you dont actually have a faulty pedal or TB unit ? ( or wiring issue )

inspector12

Another thing is can they be calibrated with a tech 2 or something from the dealer so that they read closer and don't set the code so easily?? I sent you picture of two of the TB's I have to lend for experimental purposes.

FMX05

My Centri car will go into rep if I have to pedal it really hard and I'm flowing nowhere near the air you are. It will also trigger it if I very quickly chop the throttle at high rpm. I have logged it and it's the same issue you have. ETC desired differs from actual by as much as 25%. I am using an ls2 throttle body. It really limits the way I drive the car in 2nd and 3rd gear while managing wheel spin. I haven't made a hard launch with it yet but hopefully I don't have issues there. If I do I'm going to light it on fire.

Turbo-Geist

Thanks for posting up your results. It's good to know I'm not the only one with the problem. From what I can tell, if you go to WOT on the launch and don't lift, it works. I need to get to the track and test it out. Basically, if you have to lift go ahead and grab 2nd or abort the run. What adapter harness are you using for the LS2 TB?

FMX05

Casper

wesam

I'm in the same boat but i'm ising EFILive
But my C5 is going to REP just when it goes in boost in partial throttle then As soon as i release it it will go to REP with P1516
This just happened with NW 102 and new Boosted NW102
But never with LS7 throttle
After alot of loging i found that the actual ETC is going higher than desired ETC in a place that does not have boost ( 25 kpa ) so its not boost pushing related
I'm going to try changing some parameters within few days and will keep you updated

EvilZ02

I was having this same problem when getting into boost, never while driving easy so thought it was tune related. Couldn't figure it out for months as everything in the tune looked good. I decided to cut and solder where the Casper and main harness connects and it completely fixed the problem. Guessing something was loosing contact when the motor was flexing under torque. Just something easy to look at. Harness was brand new.

stevieturbo

But if the blade is not behaving as expected vs desired blade vs pedal movements...then there is a problem. disabling safety features when electronic throttles involved could carry huge risks.

And you seem to be verifying that there are large discrepancies vs requested blade position and actual blade position ? That is something that an ecu cannot and should not ignore.

Most of the comments here seem to suggest everyone is either using a different blade from stock or an aftermarket blade though ?

Or are some using the exact blade that should be used for that car/ecu configuration ?

wesam

I logged those PIDs and some extra PIDs but my Pedal never go more than 100% also my ETC and ETC Dsrd are almost the same all the way but will different by 1-2% while throttle transitions
REP will come when the difference will be >30% ( in my case ETC =14% ETC Desr = 8% )
In your case i think you have faulty Pedal

Pekka_Perkeles

I seriously doubt.

Otherwise it would go REP without engine running but key on and just testing the pedal between zero and WOT...

Turbo-Geist

Surprise, surprise. A quick search turned up another car that logged more than 100% Pedal.

https://www.hptuners.com/forum/showt...ition-over-100

Turbo-Geist

What codes are you both getting when it goes into REP mode? Wesam, I see that you are getting P1516. Is it always this code? Also, the LS7 throttle body worked on your car? What was the part number?

I have a thread going over on HPTuners. I would appreciate if you would post in that thread just to let them know this isn't an isolated incident.
https://www.hptuners.com/forum/showt...d+Engine+Power

Turbo-Geist

So you just cut both connectors off the Casper's harness and the factory harness and soldered the correct wires together and the problem was solved?

Turbo-Geist

Let's get the 1st part out of the way: Do you work for HPTuners? This sounds like something they would say. It doesn't matter how many times you repeat the phrase "could carry huge risks" or something similar. I've already said it. I'm not interested in the factory fail-safes. At this point, the car doesn't behave in any way like the OEM intended.

It's interesting you mention this is something the ECU cannot and should not ignore. "Should not" is questionable, but "cannot", I disagree with you. The coding and calibrations are there to enable #HPTunersREPMode. This means those things can be changed. It's just another table, scalar, and/or parameter that we need access to modify. They recently gave the C6 crowd the ability to modify the values that dictate P1516. My understanding is it allows the throttle mismatch to endure for a few milliseconds longer than factory setting and this fixes the issue. They don't want to provide the same fix for the C5 crowd.

I'm using a factory non-ported LS2 throttle body with a harness specifically made to convert from an LS1 to LS2 throttle. This is a very common swap to allow more airflow and the ability to use different intake manifolds. I never had an issue with the LS6 throttle body but that was with the stock engine and this combo makes a lot more power now. Going back is not an option, I'm willing to pursue. The LS1/LS6 intake will not fit these rectangular port LS7 heads and the LS6 throttle won't bolt up to the LS7 intake that is on the car.

I'm interested in any help I can get, but leave the Doomsday drama out of this thread. I'm not buying it.

EvilZ02

Yes.

Turbo-Geist

What additional PIDs are you logging? Does EFIlive seem to have any additional things that can be changed related to the ETC?

You are seeing REP anytime the difference is greater than 30%?

I guess it's possible it could be a pedal issue, but I can floor it in third gear and it doesn't go into HPTuners REP mode. I haven't exactly been nice to the pedal through the years. Lots of WOT.