PRNDL Display Issue

[LaTechGTO]

2004 GTO - Originally a T-56 equipped car; Now has a 4L80E. The car currently drives and auto shifts perfectly fine.

This has me scratching my head, and I can't seem to figure this one out. I have been in the process of trying to upload a factory automatic base file in my PCM for almost a year and a half to hopefully clear this up since my car was originally equipped with a manual transmission, but I haven't been able to get the last few items worked out that would allow me to do so. Any input would be GREATLY appreciated!

2 Issues -

1.) Gear selection not displaying properly in the dash

2.) Commanded Idle RPM before the "System Check" = 0 RPMs


Here are the scenarios for the 1st issue since I have a separate thread about Issue #2:

*I have converted the cluster to an "automatic" version with a Tech2 (same as using the VZClusterMod) so "PRND321" is displayed.

*The PNP switch is wired up correctly and functioning as it should. It is actually from a 05/06 model, but all GTO models with a 4L60/65E have the same PNP Switch.

*As soon as I turn the key on, the PRNDL displays that I am in "P" - This is correct since the selector is in "P". I need to check other gear positions for "Key On"

*Once the car is started/running, moving the gear selector through each position displays correctly in the dash for "R", "D", "3", "2", and "1". Will not display "P" or "N" when selected.

*With the selector in "P" and the dash displaying the same when the car is started, it will not return back to "P" in the dash until the car is turned off and back on.

*If I move the selector before the 'System Check' starts, the display in the dash will move through every one of the correct gear selections, even "P" and "N".

*As soon as the 'System Check' starts, the gear selection in the cluster is stuck at which ever gear it was in when the "System Check" started. It will not move again until the car is started.

*With the car started in "P", the display will never display "P" again once it is moved from there initially and never "N".

FWIW = I've verified each of these scenarios with PRNDL and VATS active in the tune and performing a "Write Entire". I would toggle them (and test) with "None" between test scenarios to make sure it was being written. For some reason when I would try to link VATS, it still acted like it wasn't getting the permission it was suppose to - It would fail the security connection once, but the second time (after the 10sec delay), it would work. The PRNDL on/off definitely works because the display in the cluster wouldn't even move before the security check; I need to verify it will move once the car is started though - not sure if it will default to line pressure / solenoid activation and send the message to the cluster or if it won't send anything. The PID for PRNDL in the VCM scanner reflects the display in the cluster.

It seems like something is in the background of the PCM (or maybe the PIM or BCM; I'm working with a few other people to see if the PIM stores transmission data like the 05/06 model PIMs - separate TCM) that is telling the car that there isn't a PRNDL installed once the "System Check" is started; having the PRNDL set to active in the tune is allowing the signal to come from the transmission still, but the PNP isn't able to relay the information. So far it appears that the system gets all of its trans info from the PCM so maybe a full flash from a GM 2004 Auto GTO will be the cure. I am thinking the solenoid position / line pressure is delivering the gear position information to the cluster since "P" or "N" position isn't being sent to the cluster after it is started.

Cliffs:
Before "System Check" - gear position comes from the PNP.
After "System Check" - PNP can't deliver a signal for gear position.
After "System Check" and engine started - gear position is delivered from solenoid activation / line pressure; "P" and "N" signals are dead because of this.

Is the only way to get around this hurdle to upload an automatic file for a 2004 GTO from GM (ex. TIS2WEB)?

Thanks!

[DSteck]

I don't have your answer, but when I converted a manual 2004 to automatic with my own wiring harness, I flashed the cluster with the VZmod deal to an auto and did a write entire with HP Tuners on the PCM with an auto file, and the PRNDL display functions totally normal. Are you using a segment swapped file of some sort?

[LaTechGTO]

I don't have your answer, but when I converted a manual 2004 to automatic with my own wiring harness, I flashed the cluster with the VZmod deal to an auto and did a write entire with HP Tuners on the PCM with an auto file, and the PRNDL display functions totally normal. Are you using a segment swapped file of some sort?

Very interesting. I am, in fact, segment swapped since I have a 4L80E, and I'm controlling it without any relays, resistors, etc.

Here are some things I figured out today after some tinkering...

I kept thinking that loading my completely stock file manual with PRNDL enabled, VATS set to 'None' and transmission type set to 4L60E would be a good idea to do some troubleshooting. I tried a Write Entire with the completely stock file and then tried to perform a Write Calibration Only with the aforementioned changes. For some reason it started giving me some weird issues with the Editor - It first tried to make me license the file even though it's already obviously licensed. On the next try, it told me "Security Access Denied - Exceeded Number of Attempts" then went to "Security Access Denied - Invalid Authorization Code". I had a mini freak-out because it kept saying that over and over, and all I can think about is how I need my car mobile since I am having to load it to be shipped this coming Thursday. I waited a while, and I FINALLY got the 3 bar tune back in the car. Once I got that file back in the PCM, I felt comfortable making "Write Calibration Only" changes, but I still got the same errors from time to time; the only cure seemed to be waiting for something to time-out in the background.

Every since I tried to relink VATS the other day to do some testing, I keep seeing "Sending Authorization Codes" in the status box during the calibration process. It has been failing once, 10sec countdown to try to resend, and then it will proceed. It's like something isn't kosher in the tune now that I tried to relink VATS and have it set to 'None' now.

Continued... Once I got the 3 bar setup back on the PCM. I realized that with PRNDL enabled and after the "System Check" was completed, the display in the cluster would display "P" the entire time, but HPT would change from "P" to "D4" once it was completed; I didn't notice this until I set all of the in-gear idle RPMs to "0" because for some reason I was thinking HPT was saying "P" as well as the cluster, however I had my suspicion it was pulling the in-gear idle RPMs and idle airflow data. When the car is started and still in "P", HPT says the car is still in "D4".

I changed the PRNDL to "None", and the result is somewhat similar - The cluster goes from "P" to "D2" once the "System Check" is complete (same in HPT), but once I turn the key to start the car, the PRNDL in the cluster and HPT goes to "P". The correct idle tables are then used; "P/N" tables are FINALLY being utilized for idle settings!!! What is kind of weird is that the cluster will show "P" when in "P", but it will show "P" again when in "N". I can live with that, but there is still a part of me that wishes it would display properly, especially since I went through all of the trouble to wire up the PNP.

[LaTechGTO]

I eventually plan to change the transmission type to 4L60E from 4L80E in my segment swapped file to see if that has any bearing on the display.

Also, I would absolutely LOVE to find a way to keep this authentication process out of my status box when trying to write a calibration if anyone has any clue how to remove it. It seems like it wouldn't be there if VATS is set to "None". I think it would be easy to do, but I can't seem to figure it out. I have a feeling I need to go back to the original stock file for it to make the changes in the PCM/BCM link then have to come back to my segment swapped file, but I am afraid to try that again until after the car is delivered to the new location.

Thanks!!!

[LaTechGTO]

Very interesting. I am, in fact, segment swapped since I have a 4L80E, and I'm controlling it without any relays, resistors, etc.

Here are some things I figured out today after some tinkering...

I kept thinking that loading my completely stock file manual with PRNDL enabled, VATS set to 'None' and transmission type set to 4L60E would be a good idea to do some troubleshooting. I tried a Write Entire with the completely stock file and then tried to perform a Write Calibration Only with the aforementioned changes. For some reason it started giving me some weird issues with the Editor - It first tried to make me license the file even though it's already obviously licensed. On the next try, it told me "Security Access Denied - Exceeded Number of Attempts" then went to "Security Access Denied - Invalid Authorization Code". I had a mini freak-out because it kept saying that over and over, and all I can think about is how I need my car mobile since I am having to load it to be shipped this coming Thursday. I waited a while, and I FINALLY got the 3 bar tune back in the car. Once I got that file back in the PCM, I felt comfortable making "Write Calibration Only" changes, but I still got the same errors from time to time; the only cure seemed to be waiting for something to time-out in the background.

Every since I tried to relink VATS the other day to do some testing, I keep seeing "Sending Authorization Codes" in the status box during the calibration process. It has been failing once, 10sec countdown to try to resend, and then it will proceed. It's like something isn't kosher in the tune now that I tried to relink VATS and have it set to 'None' now.

Continued... Once I got the 3 bar setup back on the PCM. I realized that with PRNDL enabled and after the "System Check" was completed, the display in the cluster would display "P" the entire time, but HPT would change from "P" to "D4" once it was completed; I didn't notice this until I set all of the in-gear idle RPMs to "0" because for some reason I was thinking HPT was saying "P" as well as the cluster, however I had my suspicion it was pulling the in-gear idle RPMs and idle airflow data. When the car is started and still in "P", HPT says the car is still in "D4".

I changed the PRNDL to "None", and the result is somewhat similar - The cluster goes from "P" to "D2" once the "System Check" is complete (same in HPT), but once I turn the key to start the car, the PRNDL in the cluster and HPT goes to "P". The correct idle tables are then used; "P/N" tables are FINALLY being utilized for idle settings!!! What is kind of weird is that the cluster will show "P" when in "P", but it will show "P" again when in "N". I can live with that, but there is still a part of me that wishes it would display properly, especially since I went through all of the trouble to wire up the PNP.

I forgot to follow-up on this - I found out that I somehow accidentally tunerlocked the file a few months back, but it didn't seem to take effect until I tried relinking VATS. I finally figured out what was going on, removed the tunerlock, and was able to make some changes. Since the majority of my belongings haven't been shipped down yet, I have been really hesitant to try to do too much and risk having a bricked ECU.

After doing some minor testing, I think I am just going to have to deal without getting the proper "desired idle RPMs" until I am able to write the ECU with a GM factory tune from a Tech 2. There is something in the system won't let my PNP switch communicate with the ECU after the system check is complete and pressure is built in the transmission.

I eventually plan to change the transmission type to 4L60E from 4L80E in my segment swapped file to see if that has any bearing on the display.

I haven't had the time to test this yet, but I am doubtful that this would work.

DSteck- IIRC, the car you were tuning was a 2004 GTO with a 4L80E swap. I believe the owner didn't have a PNP switch installed and didn't want to have to do the necessary wiring for it either. You had mentioned setting PRNDL in the tune to "None"... do you recall if the symptoms were the same as I have described? Ex. "desired idle RPMs" set to 0 until the system check was complete and also the switch over from D2 to P once the cranking motor built trans pressure. Is the car you mentioned above the same car I am thinking of? Maybe it was a different car since I would think a PNP would need to be wired up for everything to work correctly.

Thanks!

[DSteck]

The 04 that I built a harness for to go manual to auto went 4L65. His PRNDL display works on the dash.

The 06 I did received a 4L80. His PRNDL doesn't work on the dash, and I suspect it's because the BCM isn't programmed as an auto.

Both have PNP switches on the trans.

[LaTechGTO]

The 04 that I built a harness for to go manual to auto went 4L65. His PRNDL display works on the dash.

The 06 I did received a 4L80. His PRNDL doesn't work on the dash, and I suspect it's because the BCM isn't programmed as an auto.

Both have PNP switches on the trans.

I thought you said he didn't have one installed - here: http://www.hptuners.com/forum/showth...-determination

Maybe this is a different setup. I'll try to post a log tonight of what I'm seeing.

Edit: just realized it was a 2004 GTO setup in an Impala, not a GTO.

[JHPerformance]

Might be completely wrong, but something in the background of the BCM could be messing with your PRNDL

[LaTechGTO]

Might be completely wrong, but something in the background of the BCM could be messing with your PRNDL

Could be, but don't think the BCM holds any transmission information. I have been really busy since I moved, but I have been wanting to try an auto PIM in my car to see if everything is resolved. Also, I am still trying to work out the logistics of trying to get a legit A4 2004 GTO file segment swapped with a FF "603" file and also segment swapped with a 4L80E file. Since I am limited with licenses, I don't think I can achieve this unless I license the A4 GTO file and license a separate "603" file I have right now and segment swap it with a 4L80E file I am running. I just don't want to end up pissing away a bunch of money for no result.

Something else I just noticed here recently was that even though the PRNDL switches from D2 to P during startup, the current gear goes from 2 to 1. I noticed this the other day when I suspected my Desired Idle RPMs wasn't pulling from my P/N section, instead it was pulling from my In Gear section, despite it is showing P in the PRNDL. Another weird quirk - I noticed the Desired Idle RPMs wouldn't gradually go down as ECT goes up like it is supposed to unless I move the shift selector from P to R or D. Even then, the Desired Idle RPMs would only change for that particular moment, and if I left it in gear, I would have to shift to P or N then back to gear to make it change. I have never noticed this before.

I straightened out a lot of things with this tune, but with other things, I feel like I am chasing my tail. I am ready to just fold and PAY someone else to finish up this tune. The startup quality seems to always be changing, even when I don't make any changes. I can literally crank the car, let it run for about 10sec, kill it, crank it back up, and it acts completely different; sometimes it over revs and sometimes it'll stumble all over itself and never get to the desired idle.

I've attached a log to show the change in the PRNDL with no change in the gear:

Idle Log.hpl
IDLE-Airflow.cfg

Please disregard all of the parameters I am logging... I am really trying to get a lot of issues ironed out and needed a catch-all config.

[LaTechGTO]

Could be, but don't think the BCM holds any transmission information. I have been really busy since I moved, but I have been wanting to try an auto PIM in my car to see if everything is resolved. Also, I am still trying to work out the logistics of trying to get a legit A4 2004 GTO file segment swapped with a FF "603" file and also segment swapped with a 4L80E file. Since I am limited with licenses, I don't think I can achieve this unless I license the A4 GTO file and license a separate "603" file I have right now and segment swap it with a 4L80E file I am running. I just don't want to end up pissing away a bunch of money for no result.

Something else I just noticed here recently was that even though the PRNDL switches from D2 to P during startup, the current gear goes from 2 to 1. I noticed this the other day when I suspected my Desired Idle RPMs wasn't pulling from my P/N section, instead it was pulling from my In Gear section, despite it is showing P in the PRNDL. Another weird quirk - I noticed the Desired Idle RPMs wouldn't gradually go down as ECT goes up like it is supposed to unless I move the shift selector from P to R or D. Even then, the Desired Idle RPMs would only change for that particular moment, and if I left it in gear, I would have to shift to P or N then back to gear to make it change. I have never noticed this before.

I straightened out a lot of things with this tune, but with other things, I feel like I am chasing my tail. I am ready to just fold and PAY someone else to finish up this tune. The startup quality seems to always be changing, even when I don't make any changes. I can literally crank the car, let it run for about 10sec, kill it, crank it back up, and it acts completely different; sometimes it over revs and sometimes it'll stumble all over itself and never get to the desired idle.

I've attached a log to show the change in the PRNDL with no change in the gear:

Idle Log.hpl
IDLE-Airflow.cfg

Please disregard all of the parameters I am logging... I am really trying to get a lot of issues ironed out and needed a catch-all config.

Correction - It *is* still referencing the In Gear and Park/Neutral tables correction in the Idle Airflow sections, but it isn't matching the Desired Idle RPM table for In Gear or P/N. Also, it isn't following the progression noted in the tune for the ECT vs Desired Idle RPM if the scanner is being used. Any ideas here? I made a few different tunes with those values zero'd out to see which it was referencing.

I did more tuning earlier, and MAAAAAAAN, my faith in the car has been restored. I am MUCH happier with some of the changes I made. Like a completely different car.

[LaTechGTO]

I think I corrected issue #1 by adding the auto transmission diagnostic segment to the file (not sure why this mattered).

Issue #2 fix documented here: https://forum.hptuners.com/showthrea...cally-Changing

[mbray01]

Going back to the original problem, dave steck had the right idea, the vehicle needed a write entire of an auto calibration, then segment swap the 80e file. Hindsight is 20/20, but definitely useful info here

[LaTechGTO]

Going back to the original problem, dave steck had the right idea, the vehicle needed a write entire of an auto calibration, then segment swap the 80e file. Hindsight is 20/20, but definitely useful info here

Yep, goes to show there is a lot going on in the background. I'm still baffled as to how the "Engine Diagnostic" segment kept everything from working correctly. Adding it was just my version of grabbing for straws lol.

[mbray01]

Likely some enable/disable switches or tests that have to run to enable something that are disabled. It's hard to understand everything going on when you can only see less than 10% of the code