2003 LB7 corrupt vin issue

[johnj]

Hi all. I tuned a truck for my boss several years ago and everything had been fine until the truck sat with dead batteries for a few months while the engine was replaced. Now it has a security light but starts and runs. When you try to flash it I get that the controller is locked with a custom key. Doing an obd read it shows the vin as a bunch of characters. So we replaced the ecm after doing some research on here and now this ecm has the same thing. Locked with a custom key message and the vin is corrupt. When I flashed the new ecm I used a known good dsp os that I had. What could be causing the corrupt vin?

[Lennydmaxguy]

Your post is cut off, so I'm not sure I have the whole story, but you might have something interfering with communication. On my LLY, sometimes my aftermarket radio does this, and my flashscan goes through about 4 different keys before giving me the "locked with custom key" error. My ECM isn't actually locked, but the flashscan isn't getting through to it.

[johnj]

Ive tried bench flashing this one and its still locked. Nothing to do with the radio or anything wires in aftermarket.

[killerbee]

You have 2 bad ecms. I have seen scores of them. Early gen ecms were tuned by someone who executed a script that left the VIN garbled. I have never been able to restore one of them in 20 years.

[johnj]

Killerbee. I transferred the correct vin from the original stock file that was read out of the truck. In the ten plus years that that truck had ran prior to pulling the engine and it sitting for two months, I had made several revisions to the tune and never had an issue until it sat with dead batteries. Now this new ecm does the same thing with a known good file of a different os that I have used dozens of times without a single issue. It makes me think theres an issue with the truck causing the vin to be scrambled. Or did I just get another bad ecm. You know far more about it than I do its just odd.

[killerbee]

I think you got another bad ecm. I have a pile of them in boxes, alongside my replacement stock. The staff here may be able to explain more about the LB7 garbled VIN. When you interrogate the ecm does it still have a serial number? These are 20 years old, and were not very robust ecms when they were new. You are welcome to send it to me, and I can take a peak at it off-board. But as I said, I cant recall recovering one.

[johnj]

A bunch of zeros and an h is all the serial shows

[killerbee]

A bunch of zeros and an h is all the serial shows

The ECM is toast. Email if you want one that works.

[johnj]

Sounds good. What is said email?

[killerbee]

message me