viciousknid

iTrader: (8)

My PCM took a dump on me mid transfer. Got it swapped and running again thanks to some great people at EFILive.
But it got me wondering about a few things and I was hoping you guys could take it off my mind for me.

When people buy a PCM online for a spare, are they also buying a new License so that they can use it.
If they don't have EFI/HPT are they just going to a dealer?

According to what i read on EFILive. When you swap the PCM you have to do a VAT relearn.
When someone gets a tuned PCM from a mail order tuner. How are they doing this if they don't have tuning software?

Just some things that crossed my mind and was curious about.

GMCtrk

iTrader: (27)

I don't know what a "VAT relearn is"

I've put at least 3 different PCMs in with no problems.

howard quick

Hi Josh,
as far as I understand it...when you use EFILive or HPT or similar...you buy a licence for each PCM.
So...if you buy a PCM from Ebay or a junkyard or whatever...you need to buy a licence from your tuning software vendor to be able to tune that new PCM.
If you don't have tuning software wich is capable of doing a VATS (Vehicle Anti Theft System) relearn....most guys take their trucks to the local dealership.
With the OBS trucks a crank relearn is needed.

chevrolet all the way

iTrader: (24)

if thats the thing im thinkin it is, you have to try to crank it turn key of for 30 sec leave key on for 11 min. and do that 3 times. thats all i had to do but wheatley sent mine im not sure if there are other things to do

sonoma43

iTrader: (1)

You have to turn the key to the on position until the security light goes off then turn the key off, do that 3 times then it should crank over and fire.

viciousknid

iTrader: (8)

EFI has a VAT relearn in the Tune software. Flash > PCM Security > VAT Relink. For those who don't know, you can also change the VIN there instead of using the Scan tool.

I'm fixing to do some searching to see what the Crank relearn specifically does, cuz now that i did the swap, my washer fluid won't spray.

As far as my questions go, I suppose everyone just buys another License. and the Mail order guys either Don't need a Vat relearn or just run it by the dealer.

Here's EFILives definition of a VAT Relink.
"The security system in your vehicle usually requires that the PCM and the BCM (Body Control Module) negotiate a number of electronic messages until they both agree that the cranking attempt is legitimate. To facilitate these negotiations, the PCM and BCM must be linked with a “trusted” connection. This prevents bypassing the security system by simply replacing one or both of them with a compromised unit.
If you ever replace your PCM or BCM, then you must re-establish the trusted link between the PCM and the BCM. EFILive can do that via the VAT re-link process.
When you click on the [VAT relink] button, EFILive instructs the PCM to set a flag that will cause it to re-link to any BCM (that it can “see”) when the ignition is next switched on."

howard quick

The other possibility is that with a mail order tune (assuming using a diffeent PCM) the tuner possibly disables VATS.
I have a 99+ PCM in my 98 and I disabled VATS.

viciousknid

iTrader: (8)

Very good point.

viciousknid

iTrader: (8)

well. I'm going to run outside and see if I can salvage my stock PCM or not. If i can I'll have two. If not, $78 core.

viciousknid

iTrader: (8)

Old PCM is junk. But found out something else.
I usually drive with my windows down, but had my nephew with me today so I was gonna run the AC. and now the A/c won't come on. A/C, Recirculate, and Rear defroster. None of the lights will even attempt to come on?

Think that has to do with a VAT relearn to sync the PCM and BCM? I never could get it to work.