CCLB dually #2

[Supercharged111]

Well ****. VATS?

https://www.gmt400.com/threads/lq4-swap-fires-but-wont-stay-running.44355/#post-1039568

There goes $120.

 

[JSlezak83]

I was thinking VATS, but wasn’t able to reply in time.

 

[Supercharged111]

Seems there's a resistor mod I can do, gonna try that first.

 

[JSlezak83]

Is that for the black box pcm, or the older models with a separate VATS module?

 

[Supercharged111]

Black box, I know a guy who did it to a 99 Tahoe.

 

[Supercharged111]

So apparently there were 15 different resistance values used in the GM keys, but none of my truck keys appear to have a resistor in them? Does anyone have a schematic for the VATS system? I'll go check my pinouts, but it sounds like GM had the key report to the BCM for this? I wasn't even aware these trucks had BCMs.

 

[JSlezak83]

I’ll check the service manuals tomorrow, but I believe only the Escalade/Denali had a BCM. These keys don’t have the chip like the older style GMs.

 

[Supercharged111]

Slowly but surely my google fu has prevailed.

https://www.gmt400.com/threads/how-to-bypass-the-security.39407/

Post 4. Now to find an 2200 ohm resistor.

I have to wonder, since the truck started life as a diesel, did it have Passlock? The diesel used an old style computer behind the glove box, not the one that lives under the hood expecting a handshake from a VATS module that lives under the dash.

 

[skylark]

Slowly but surely my google fu has prevailed.

https://www.gmt400.com/threads/how-to-bypass-the-security.39407/

Post 4. Now to find an 2200 ohm resistor.

I have to wonder, since the truck started life as a diesel, did it have Passlock? The diesel used an old style computer behind the glove box, not the one that lives under the hood expecting a handshake from a VATS module that lives under the dash.

98+ including diesels had it. No chip in the key. It is looking for rotation of the lock cylinder. I've bypassed it before using the 3 wires on the lock cylinder and a resistor then perform a relearn.

 

[Supercharged111]

Good to know, I want to squash this on my first try. I still can't believe how instantaneously the thing fired yesterday. That motor hadn't run since April 2018 and even then the truck it came from had sat for a long damn time.