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Repeating Fault Code 75

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I'm running into an issue where i keep getting a fault code 75: Throttle plate position unable to maintain or achieve the desired target position. I've redone the TPS calibration procedure multiple times, i've replaced the throttle body with a new unit and i've switched out the accelerator pedal thinking it was that as well.

This issue started happening after an alternator went out , it was replaced with a new one and  that's when i've started having issues. This is mainly happening at the track. Before this weekend i replaced the throttle body with a brand new unit and i spent two  30 sessions this past weekend going around a track at slow speeds during the rain and there were no issues, no codes popped up so i thought the new throttle body fixed it.  Once the track dried up i was able to go WOT and get on pace and that's when the code would start popping up and the car would go into limp mode. sometimes the car would go into limp mode right after turns where i'm feathering the throttle and then sometimes The fault code pops up randomly and i cant figure out why. 

2005 R53 Mini cooper

i have data logs of the last session and the map. 

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Can you please post the actual log? there are 3 or 4 error counters around main vs sub correlation, AP target vs actual correlation etc, and we need to see which one is tripping.

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Unfortunately that log doesnt contain values for TP Error Accumulator or TP/Target Error Accumulator. If we cant fix it here, add these 2 into the logged parameters for next time so we have better info next time it faults.

For now, we can see here that the accel pedal has no issues and rule that out - both main and sub track nicely together and show no AP errors

Comparing TP main & Sub we see the 2 of them track together quite nicely so its unlikely to be a TPS error. These 2 values seem to be within 0.2 - 0.3 at all times which is fine.

comparing e-throttle target against TP main & Sub postitions however, we see that every time you get off the throttle, the TPS postition almost "bounces" back up a couple %. Usually this is caused by PID setting issues in the ethrottle control. in your case it looks like they might be a bit too aggressive, and its causing some pretty bad overshoot (and for it to not quite oscillate, but still jump back in the wrong direction once it overshoots). This screenshot shows the worst example I could find of both the "bounce" when you go from full throttle to 0%, and for general poor tracking of target -> actual TPS angle. Note the blue TPS line overshooting by 10% ish repeatedly between 10:04 and 10:08. There is another good example at 13:40 +/- 5 seconds.

I'd suggest setting your ethrottle to "always run", then with the engine off, tune your PID settings a bit while logging these same values, until you get TPS to track target reliably thorugh both slow and fast throttle transitions

image.png.d367b3a49145e824ceb99fb88f6505cf.png

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Its almost definately TP/Target error due to PID, you can see it is the first screenshot oscillating in a couple of areas.

I would try dropping the P down to 8.5 and bump the D up to 40.

 

eq1fsg.png

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CJ,

Thank you for the input, i really appreciate it. I will add those parameters to my ecu logging and see I can replicate it on the street. Just curious are there parameters that you recommend being logged at all times for troubleshooting purposes? i know we are limited on the number when we are logging on the ECU. 

 

Adamw, 

Thanks, i will try to replicate the issue with the current settings with the additional parameters and then try adjusting the P&D settings to see if that works. 

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Those arent parameters you would normally worry about once you have a "happy" ethrottle. As far as I understand it the logging is limited to a certain number of MB, and the more parameters, the quicker you fill it up, so you just reduce the amount of history/time you can hold in the ECU.  

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i didnt see a  TP/Target Error Accumulator, that was only an option if i had a E-throttle 2 sensor which i'm only running E-throttle 1. 

I wasnt able to drive the car since it was boxed in the garage due to a hail storm heading our way last night. I set the e-throttle set up mode on and played with the throttle to see if i could replicated the bouncing while coming off full throttle and it didnt seem to happen. I changed the settings to p-8.5 and D=40 and it looks like it made the TP and target further off.

Log 2019-04-17 6;46;52 pm settings changed to p=8.5 and d=40.llgsettings left as is which had issues with engine running.llgLog 2019-04-17 6;44;05 pm settings left as is which had issues.llg

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The error accumulators are showing zero in all of your logs so no "smoking gun" yet.  But the log with the adjusted PID does show more stable control so I would keep those changes for now.

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So i finally had time to try to get fault code 75 again with my original settings. the TP would trace well when i was in the right gear but when i upshifted and played with the throttle at low rpms the TP  and Ethrottle target would go off going into limp mode. attached is my log. 

Log 2019-05-7 5;18;16 pm track car.zip

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Is that the right log?  At what time section did it go into limp mode?  Also as CJ mentioned earlier you havent logged the TP/target or TP error accumulator so it makes it pretty difficult to see what is causing the problem.

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