8L90 PRNDL status shows UNKNOWN 82

[COPO2014]

I have a somewhat bastard situation. Might be a long read but would appreciate some insight Thanks

Anyway,

I bought a GEN 5 LT and 8L90 out of a wrecked 16 Camaro. I did receive the ECM and TCM with it, however I bought a 2017 Camaro that was a repo car with no motor/trans and put the engine/trans in it. I did not get a ECM for the car but I couldn't use the 16 ECM being a e92 not a e92a. I had someone supply me a E92a for the car. The transmission was just gone through and had a valve body replacement, I went into TECHLINE CONNECT and updated the new valvebody PUN number but I couldn't update the TUN number off the trans because the tag is wiped clean. But TECHLINE took the PUN so I thought all was good. When I go to do the fast learn for trans in HPTUNERS and through TECHLINE it fails. What I did notice though was in the scanner when it is in Drive the PRNDL status shows ( UNKNOWN : 82 ) Reverse, Neutral, Park all indicate. This issue happens with the T87 and T87a installed

Attached is a side by side of the the car ECM and TCMs I had the T87 in it but it would not upload the valvebody. So I sent the T87a to be unlocked so I could add the valvebody to global.

Any help to lead me in the right direction on this as I am very unfamiliar with all of this

Thanks

[matt510]

I'm having the same exact issue with the PRNDL status showing UNKNOWN : 82 while Reverse, Neutral, and park all show correctly. the ECM and TCM are both from the same 2017
SS Camaro.

[COPO2014]

I'm having the same exact issue with the PRNDL status showing UNKNOWN : 82 while Reverse, Neutral, and park all show correctly. the ECM and TCM are both from the same 2017
SS Camaro.

Matt is the trans from the same vehicle as the ecm/tcm? I'm wondering if it has something to do with the IMS switch inside the trans. They had a 4pin and a 10pin switch I am wondering if the trans has a 4pin and the tcm wants a 10 pin or vice-versa. I think that's where I'm headed with this

[matt510]

Yes Both ECM and TCM are from the same vehicle. I did find that both pin 35 and pin 51 on the TCM connector needs to see 12 key on power. I wasn't getting 12v on pin 51. Once addressing that it still shows Unknown :82 but it is now shifting through the gears.

[COPO2014]

Yes Both ECM and TCM are from the same vehicle. I did find that both pin 35 and pin 51 on the TCM connector needs to see 12 key on power. I wasn't getting 12v on pin 51. Once addressing that it still shows Unknown :82 but it is now shifting through the gears.

What about the transmission is that from the same car?

[rpmextreme]

I think out may be a HP tuners scanner issue showing Unknown 82 while in drive and manual mode. I have seen this on several working, driving 8L90s wi no issues. I think maybe they don't have their parameters set right on HPT side so it displays Unknown 82, Unknown 81 etc..

[Owtcast]

I've been struggling with this same issue for a while now. Matching 2017 L86/8L90 from GMC Sierra Denali. The problem seemed to escalate from what began as a loud squealing noise in the transmission while driving that would continue through all forward gears until coming to a complete stop. Upon reacceleration, it would no longer be present and would randomly reappear, always with the same result. Squealing, complete stop, pull away normal. I figured I had a solenoid going bad and damaging the hardware, so I rebuilt the transmission. All new wear items, billet torque converter, internal harness, and valve body. Reinstalled and still did the same crap. The next time I attempted to drive it, it wouldn't go into any forward gear. Park, reverse, neutral, all fine and registered accordingly. Any forward gear shows "Unknown".