2003 Trailblazer EXT 5.3 Crank but no Start and BCM issue?

Viperhawke · February 16, 2017

Hi Guys,

So I have a 2003 TB EXT 5.3 that was involved in a flood. Water came to below dash and a little in the rear pass cylinders. Everything has been cleaned and dried out. New battery, plugs, wires, etc.

She cranks great, but refuses to start. There is spark, fuel, and compression from what I can see but did not verify that part. I did swap the BCM from another trailblazer I had access to a few years ago. At this point, by a local ASE mechanic, I've been told the BCM needs to be programmed for my truck to start.

I've even done that pass key procedure.

Any other advice? Does the BCM need to be reprogrammed if it came from another TB? Anything else I could check? BTW, the radio does show locked. Thanks in advance!

Viperhawke · February 16, 2017

So it seems I may have posted in the wrong area, could a mod move this for me if so?

SpartanAutoworx · February 17, 2017

Does the security Light flash?

If so you need to do the 30min relearn procedure. I have a video on youtube that covers the procedure just look us up.

On the issue of programming should you get it flashed.. Yes Required depends.. If the truck has the same options you should have no issues except the RDS radio will be locked as the BCM vin does not match that of the RDS Radio. You can reprog the BCM or have the radio unlocked / reprogramed to match that of the BCM to regain radio operation. The correct way would be to reflash the bcm per your vin via SPS.

Hope this helps.

Viperhawke · February 17, 2017

Well the security light doesn't flash because as I mentioned I did the pass code procedure already. I will post a video of what happens when I try to start and maybe someone can help from there? As far as getting it programmed... It should still start right? What if the donor vehicle was a 4.2 and mine is a 5.3...just wondering.