How can I stop P1516 and P2101 codes?

[Fulton 1]

I am very new to tuning and HPTuners and I need some help dealing with a ported TB. Since I installed this ported TB I am getting periodic P1516 and P2101 codes. Sometimes I get Safe Mode and the car dies and sometimes not. The thing is that the car drives great with this TB and the throtle response is awesome so I hate to give up on it.

Is there any way that I can either disable the P1516 and P2101 codes or otherwise adjust the TPS parameters to prevent this on-going problem?

I appreciate your help and apologize if this is a basic question.

TIA

Joe

Attached is my current tune. Engine is internally stock 05 M6 with only mods being LPE CAI, catback, ported LS2 intake, ported LS2 TB, and Kooks LT's.

[Fulton 1]

Whoops, here's the current tune

[Russ K]

Your going to need a service manual or ALLDATA to diagnose the TAC codes. There is nothing in the tune for these codes.
Check your connection at the throttle control motor, pinched/shorted wiring.

Russ Kemp

[Fulton 1]

Your going to need a service manual or ALLDATA to diagnose the TAC codes. There is nothing in the tune for these codes.
Check your connection at the throttle control motor, pinched/shorted wiring.

Russ Kemp

Thanks for the reply, Russ. I have the Helms manual and have run through the diagnosis. The TB (in theory) and connector/harness are fine, but I believe that the TB was damaged in the porting process. I have replaced with a known good TB and the codes do not reappear (although I now get a fluctating idle upon coastdown that I need to address). After some research it seems that the LS2 TB's are very finicky about having their throttle blades removed during the porting process. This is my first experience with it.

According to the Helms manual, there is a "calibration" (nothing more specific than that) between the two TPS sensors that, if exceeded, trigger the DTCs and subsequent shutdown in some cases. I was hoping that I could alter this "calibration" to make this TB usable since mechanically it functions great, but doesn't look like it.

[Mickie Poon]

I am very new to tuning and HPTuners and I need some help dealing with a ported TB. Since I installed this ported TB I am getting periodic P1516 and P2101 codes. Sometimes I get Safe Mode and the car dies and sometimes not. The thing is that the car drives great with this TB and the throtle response is awesome so I hate to give up on it.

Is there any way that I can either disable the P1516 and P2101 codes or otherwise adjust the TPS parameters to prevent this on-going problem?

I appreciate your help and apologize if this is a basic question.

TIA

Joe

Attached is my current tune. Engine is internally stock 05 M6 with only mods being LPE CAI, catback, ported LS2 intake, ported LS2 TB, and Kooks LT's.

I had the same problem after porting my throttle body it turned out not to be a tuning issue. Make sure the blade goes back as it came out. Move the blade all the way back and sweep it forward make sure there is no bind. A slight bind sweeping backwards is an indication your blade needs to be aligned differently. On mine I cleared the bind and it never came back.

[Fulton 1]

Thanks, Mickie, for the input. I am actually surprised that there isn't more talk of this problem on the boards, but I have found very little. I suspect as more people port their LS2 TB's we will see more of it. In speaking with another porter, he tells me that indeed the removal or in some cases modification of the throttle blade itself can and usually does cause this problem. I did try to reposition the blade on the aforementioned TB (actually I thought I was on to something because when I pulled the blade out I saw the original marks where it had been mounted and repositioned it to match). Seems to me that the blades must be installed this way when the TB is manufactured, so I don't see how you couldn't "get it right" as long as you spent the time to re-align it properly as you suggest. In my case there must have been some irrepairable damage done, since this didn't solve the problem for me. No matter what I tried I got p1516 again in only about 5-6 miles of driving.

I finally just gave up on this TB and installed another ported TB from a different porter who doesn't remove or modify the blade itself. While this one doesn't have the immediate responsiveness of the troublesome TB, its going on about 100 miles now with no codes. Of course, this one gives me a strange idle fluctuation (dips down to about 500rpm when coming to a stop on occasion), but I think I have been able to improve the situation by using the adaptive idle params and adjusting the idle airflow per EC Tune's recommendation on other posts.

[Mickie Poon]

If you are 100% sure it is not binding in the forward and reverse direction here is another theory of why the 1516 and 2101 gets thrown.... It is long so brace yourself:

I think I figured out why we are getting the 1516 code error and it may be a lot simpler than we think. Basically that code is set due to a correlation error meaning the predicted throttle position to actual. But how does the PCM and TAC module predict the correlation? Very simply by our idle speed adjustment meaning a 750 idle speed would usually mean 0 ohms at my pedal and let say 20 ohms at the pot that monitors blade angle or in the case of 850 idle would equate to something like 0 ohms at my pedal and say 25 ohms at the blade. Once those figures are set by the TAC and PCM it goes on the assumption 5 ohms at the peddle is equal to 20 + 5 (25 Total) ohms at the throttle blades in the case of a 750 idle, and 5 ohms is equal to 30 ohms at the throttle blade in a 850 idle. The two moves in a correlated or a synchronized fashion during acceleration, and once the correlation is set and if it goes out of assumption for more than .5 seconds the code is set.



Enough of my boring theory so why are we getting the 1516 code then? My theory is once the PCM determines a correlation it must be within the limits it has predicted. In the case of a rough idle this changes the correlation. Let’s use the 750 idle as an example the PCM believes 0 ohms at the pedal is equal to 20 ohms at the throttle blade but in a rough idle (large cam) the blade bounces around to keep the 750 idle and if it bounces too far it doesn’t know what to use for a reference. Is it using 20 ohms from the blade for correlation or 25 ohm in a rough idle? This is important because it needs to know that information to properly control the throttle blade. I am assuming once it is correlated it can’t bounce a lot, meaning the idle must be fairly steady and can’t be off it’s determine value for more than .5 seconds. If the idle is too rough the code gets thrown because it looses it predicted reference values. So why does porting a throttle body affect the 1516 code? Very simply the throttle body around the blade is contoured for idle quality meaning very little blade movements to keep the idle steady. If one ports the throttle body around the blade this affects the amount of movement the blade has to make to keep the idle steady and if it moves too far to keep things steady, once again you will get a 1516 code. Now concerning making a hole in the throttle blade it has been noted by 2 sources HPE and Katech that by doing so it makes the blade move less to keep the idle steady. This is important since it aids in the PCM and the TAC in setting and maintain the predicted correlation. So why do people who put a hole in the throttle blade not get this code? Because the PCM and TAC modules are smart meaning if the idle is steady regardless of how fast it idles it can learn the new correlation. Making a hole is different than porting because it does not affect the contours of the throttle body thus not affecting the swings of the blade to keep steady idle.



So in conclusion depending on how much the throttle body has been ported around the blade, making a hole in the blade should help however, if you still have a problem the throttle body should be changed. Regardless in an aggressive cam I believe a hole may be required. According to the Vette doctor “some engine will idle fine while others will not” in such cases they too resort to the hole in the throttle bade. HPE according to the guy that installs their cams always put a hole in the blade on the stage 3. What this means is on my setup I had to make a hole in the blade to keep idle steady. Even with a new throttle body if the blade has to make aggressive swings to maintain idle a hole may have to be made. This also explains why speeding up idle corrects or lessen the problem. Idle speed affects idle quality which affects the ability of the TAC and PCM to maintain its correlation at idle. Once again the idle correlation determines how the blade reacts once the gas pedal is depressed. Also keep in mind the TAC module can also throw the 1516 and 2101 errors which cannot be programmed out. If you were able to program this out, your car is in a dangerous situation, severe correlation errors would not be detected. Imagine going 1/8 throttle and the pcm went crazy and swung the blade to full throttle and not being able to go to reduce power mode.

In conclusion you can port a drive by wire TB but be careful around where the blade sits, preferably not to touch that area and on a large cam install a hole may be required to maintain correlation. If possible port without removing the blade this will prevent any alignment issues. This is my theory and everything I have research thus far proves this to be true.

[Redline MS]

Last time I had this problem it was a issue with the early version E40. There are some bugs within the ETC parameters that we have no control over. Chris is able to fix this if you send him the file.

Its got to do with the predicted airflow vs. limits set within the pcm to make sure the ETC is not running out of control. Since you modified the TB more air is entering then the pcm is happy with at a given throttle angle. The limits need to be opened up.

Just my guess.