Vats

[DURAtotheMAX]

Have you tried wiring in a dummy relay to the starter relay control circuit? Or put a resistor in line? So the ECM thinks a starter relay is connected.

[shay]

Have you tried wiring in a dummy relay to the starter relay control circuit? Or put a resistor in line? So the ECM thinks a starter relay is connected.

Yes

Thanks

[DURAtotheMAX]

Yes

Thanks

ok and even with the starter relay wired in, it still wont start?

So this is what your current setup is, corrrect me if Im wrong:

Standalone harness
VATS disabled with EFILive
dummy relay wired into the starter relay circuit to the ECM
no BCM
no theft deterrent module
manually jumping the starter solenoid so that the engine cranks

And then the engine doesnt fire?

[DURAtotheMAX]

https://www.youtube.com/watch?v=hVMh3Div9yk

Theres an LML swap.....but I dont know if they transplanted the entire dash/steering column/theft deterrent module, etc.

[DURAtotheMAX]

Well Im beginning to think that there is a more complex fuel-enable routine in the LML ECM....and its not just a simple VATS switch.

Anyone up for working on an E38-style VATS patch for the LML ECM?

[shay]

ok and even with the starter relay wired in, it still wont start?

So this is what your current setup is, corrrect me if Im wrong:

Standalone harness
VATS disabled with EFILive
dummy relay wired into the starter relay circuit to the ECM
no BCM
no theft deterrent module
manually jumping the starter solenoid so that the engine cranks

And then the engine doesnt fire?

Hi
It is not Standalone harness.
I try on chevrolet silverado 2012 LML with OS 12644094.(no harness change)
I disabled VATS with EFILive and disconnect the theft deterrent module connector:

Engine not crank I try to jumper the starter relay and it's not start.
I try more 4 OS with disable VATS - same.
I try global A in EFILive same.

You don't think I need to disable VATS DTC
Thanks
shay

[DURAtotheMAX]

Last ditch effort would be to wire in a resistor across the ECM relay control terminals (the terminals for the coil of the relay)...and then try jumping the starter terminals of the relay.

That way the ECM still thinks it has the relay wired in.

If that doesnt work, than we're screwed...and going to need a VATS OS patch, similar to the late-model GM gas controllers (E38/E67/E92).

Ross I know you havent worked on the LML in a while, but is there any chance you might be willing to look into this? Maybe some of the VATS/fuel-enable routines in the later E38/E67/E92 controllers carries over to the LML?

[IdahoRob]

I've swapped ecms in LML trucks without issue by turning off the vats. These were complete trucks though. Something to add that was very weird, the one truck had a code issue and wouldn't clear so I swapped the ecm out of my truck and installed into his truck. The codes then came up and corrupted my ecm and wouldn't clear. Took a Tech2 flash to fix both ecms, must of been another module in his truck.

[DURAtotheMAX]

I've swapped ecms in LML trucks without issue by turning off the vats. These were complete trucks though. Something to add that was very weird, the one truck had a code issue and wouldn't clear so I swapped the ecm out of my truck and installed into his truck. The codes then came up and corrupted my ecm and wouldn't clear. Took a Tech2 flash to fix both ecms, must of been another module in his truck.

Rob I think its when the BCM and Theft Deterrent Module are removed/unplugged (IE, in a true standalone setup) that the LML ECM gets grumpy...

Have you tried unplugging the theft deterrent module in your truck and then tried starting it?

[Chavez91]

Sounds like them CAN messages. Its possibly looking for a message that its not receiving because the module is no longer there, and its causing the ECM to freak out. Thats my best guess at the moment.