Chevy Tahoe 1997 PCM Swap to Chevy van 1999 ECM L31 5.7 Vortec

[Batlabs]

I have a 1997 Chevrolet Tahoe with a L31 5.7 and 4L60E trans, I know the 96-97 aren't supported and I didn't wanna do a 411 PCM swap so I got a 1999 Chevrolet Express PCM that also had a L31 5.7 with a 4L60E trans.
(I thought it would be Plug N Play)
I changed them and the 1999 Chevrolet Express had some DTC's and also ran ruff like it was missing on a few cylinders.
(I even cleared DTC's unhooked battery and tried again, same DTC's showed up)
DTCs on 1999 ecm.jpg

I put the OEM 1997 PCM back in it runs smooth.
The 1997 has the 5 plugs PCM with the middle dummy plug and the 1999 just has the 4 plugs.
Both ecmin tahoe.jpg
Do I have to change any pins on the PCM for the 1999 PCM to work In the 1997? I know the 1999 ran perfect when I pulled the PCM.
I looked on lt1swap.com and Googled for hours and couldn't find a answer...
Here's the 1997 PCM
1997 Chevy Tahoe ECM.jpg

Here's the 1999 PCM
1999 ECM.jpg
There are no DTC's when runnin the OEM 1997 PCM.
TIA

[Fast4.7]

The 1997 and 1999 PCMs have some slight pin changes required. On my 97 L31 Van that I repinned to an 0411 the center connector was merely two wires that looped back into the same connector. The 99 PCM also will not support the 97s EVAP pressure switch as GM moved to a pressure sensor and added a canister vent solenoid.

[Batlabs]

Thank you so much for the Input! I did alot more reading and seen there was different pinouts from 97 to 99 pcm on lt1swap... Just got back from another junkyard with a 411 out of a 2002 GMC Savana 2500 with a 5.7 l31..
Guess it's repining time with the 411!!!!
I'm gonna take the 1999 pcm back and get another 411 because I also have a 1996 truck to do.
1999 Chevy Express 5.7 - 2002 GMC Savana 5.7.jpg

[24xLT1-S10Blazer]

Hope you don't need the 97 Tahoe vin in your 411 PCM for State Inspection. I now have two 411 pcms for my 97 Silverado for NC State inspections reasons. One I can tune with HP Tuners with 02 Silverado vin and Operating System that set up for my 24X L31 Vortec and another 411 pcm that I had someone with EFI Live tuning platform set up a tune and install my 97 Vin just so I could pass inspection.

Just thought you should know what could be quite the adventure. The guy who did my EFI tune has an EXCEL spreadsheet for the 97 L31 repinning for 02 411 PCM. Good Luck Ken

[anniversaryss]

Depende where he lives. I have an 02 in my 97 SS. No VIN issues. And NYS is terrible

[Batlabs]

Don't need a vin change, no smog check where I live, in 3 more years I can put antique plates on it if I want. I got the Excel file from Lextech (if you need his Excel file PM him on one of the many forums he's on), took me less then 2 hours to do the 411 swap. I don't have HPtuners so my buddie hooked me up, we used the 2002 GMC Savana L31 411 pcm it had the 4L80E trans so he switched it in HPtuners setting to a 4L60E it shifts like it has a shift kit now and it's never run better... it did throw a P0717 Turbine/Input Shaft Speed sensor A circuit No Signal
The 4L60E never came with a Input sensor untill 2004 so we figured it was looking for the 4L80E sensor and did a segment swap off a 2002 Chevy s-10 with a 4L60E then it had to rev real high in overdrive and drive to get going but if you put it in 2nd or 1st gear it would move just fine so we put the orginal 2002 GMC tranny tune back in and switch the tranny setting to 4L60E in Hptuners. The tranny upshifts and down shifts fine now but it shifts really hard like it's got a shift kit.
Is there a different segment swap we should do for this 4L60E tranny? When I say it shifts hard I mean it will do a 1st to 2nd gear scratch... kind scary in something so heavy with a 4L60E...
Does anyone have a tune we can try? it's a 1997 Chevy Tahoe L31 4x4 4L60E with a 2002 GMC Savana L31 2x4 4L80E 12200411 pcm.

The S-10 and the Gmc both have the same OS 12212156, not sure why it was making then tranny slip when when starting off in over drive and drive but went right in gear when in L2 or L1 gear range.
Thanks Guys! will keep you posted!
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Edit: My buddie got a 2002 tune for a L31 and 4L60 and now it shifts like it did before the swap (Not Banging in 2 gear) and there's no more P0717 code. from what he was saying you can't just changed the Drop down box on HP Tuners from 4L80 to 4L60. you have to change the segments or it will still be looking for the input/output sensors on the 4L80 and the 4L60 doesn't have them. Hope this helps someone else.

[Shawn Mendes]

Here you can find an article about top 5 spark plugs for Vortec:

https://autokwix.com/review/best-spa...gs-for-vortec/