98s an passlock/vats issues.

[bluex]

The last 3 98s I've replaced key cylinders on have gave me fits for some reason. I can't get them to complete the relearn. All 3 have had badly worn keys that cause you to jiggle it to get it to turn an that results in the relearn needing to be done often with that worn key (security on solid). They come to me, I unhook the battery, replace the key cylinder, hook it back up do the relearn an it never works. Wind up with a flashing security light an the truck doesn't run but for 5 sec or so. When you turn the key on the light will go out but once it cranks, it starts flashing an kills it.

I wind up taking them an having vats deleted but I'm genuinely curious why all the sudden this is causing issues, I've done it the same way in the past with no problem. Just frustrating is all. I'm about to buy HP tuners just for thus function.

Anyone one know of a better software to do this that doesn't require credits an the like everytime.

 

[99xcss4]

I do not think there are efi live need credits jet dst comes with credits but once you use them you will need to buy more there are mail order services but then you need to send the pcm out other then that the only other thing you can do is what you have been doing go to your local tuner and have them tune it out I have heard of pcm hammer but know nothing about it and I think you might need other soft ware with it

 

[someotherguy]

Maybe quality of the replacement cylinders is slipping, like most other replacement parts these days? Wild guess, sure, but possible.

If nothing else, Passlock failure is imminent on potentially all of these 98-up trucks at one point or another, for one cause or another, so you've future-proofed them in that respect by tuning it out.

Richard

 

[df2x4]

Maybe quality of the replacement cylinders is slipping

This or coincidental, unrelated failures in other parts of the system would be my guess. They are antiques now...

 

[Supercharged111]

97 and 98 cylinders are different. I put a 97 cylinder in my 99 plow truck and it didn't like it. They look the same and fit just fine, maybe that's what's happening? The earlier cylinders don't have any resistors in them.

 

[someotherguy]

97 and 98 cylinders are different. I put a 97 cylinder in my 99 plow truck and it didn't like it. They look the same and fit just fine, maybe that's what's happening? The earlier cylinders don't have any resistors in them.

Correct. 1998 is first year for Passlock on GMT400's. The earlier trucks had no anti-theft from factory. For a 1998-up GMT400, you must use the correct key cylinder as the older ones won't work. That is, unless you're also deleting the Passlock functionality from the tune.

Richard

 

[bluex]

97 and 98 cylinders are different. I put a 97 cylinder in my 99 plow truck and it didn't like it. They look the same and fit just fine, maybe that's what's happening? The earlier cylinders don't have any resistors in them.

I told them they were 98s when I ordered, maybe I'm getting the wrong parts from the store

At any rate this one is deleted an running, albeit roughly again. I think it needs injectors (multiple misfires all on pass bank and O2 codes only on that side) but it's been sitting so the owner decided to try a new fuel filter, some fuel treatment and a splash of 93. Worth a shot before dropping the cash on them at least. Runs OK down the road but idles rough.