[Gmecm] Class2 DIY tools?

[Dustin Lof]

Phil, I have troubleshot several pass lock systems
with my BDM,  a DVOM, wiring diag., and a little
common sense. I have never held a Tech 2, Yes there
are times it would be nice but then I would need a
NGS, and a DRB.  We have to send everything out to be
flashed but other than that it all stays in-house.

As for the bravada, check fuses first, second and
third. Dustin Lof
--- Phillip Kuhn <pmkls1 at yahoo.com> wrote:

> Ok, I have reviewed the GM wiring schematics for
> this
> vehicle and this is what I can tell you. The BCM is
> NOT in control over the info coming into the
> cluster.
> The cluster recieves it's data via the class 2 data
> bus from the VCM (aka PCM) on this vehicle. Also,
> the
> passkey system in this truck does NOT go through the
> cluster, rather it is wired directly to the bcm
> which
> sends data to the VCM. More than likely from what I
> see in service information and from what you say the
> 2
> problems that you are having are completely separate
> and not related in any way, at least not by
> something
> such as the BCM. I can send you some "real" wiring
> schematics tomorrow of the cluster and passkey
> system.
> In the meanwhile my suggestions would be to first
> check ALL of the fuses as there are many that could
> affect the operation of the vehicle. Second attempt
> to
> perform a passkey relearn. And third, double check
> all
> of your connectors to make sure all of them are
> completely seated.I can assure you of this, when it
> comes to passkey in particular, there is NOT any way
> possible to perform certain functions without a tech
> 2
> and any other scan tool is not capable of performing
> those functions from what I have been told. Below is
> a
> key learn procedure borrowed from service
> information.
> 
> 
> 1. Ensure that the battery is fully charged. 
> 2. Use a scan tool in order to clear the Passlock?
> DTCs
> 3. Turn the ignition switch from the OFF position to
> the CRANK position, and then to the RUN position.
> The
> vehicle will start and then stall. 
> 4. Leave the ignition ON until the security telltale
> turns OFF in 10 minutes. 
> 5. Repeat Steps 3-5 for 2 more times (3 times total)
> 
> 6. The Passlock? controller will learn the new data
> on
> the next start 
> 7. Use a scan tool in order to clear all DTCs. 
> 
> I would at least attempt to do the key learn without
> clearing the codes as I have never had to clear them
> before programming a key. Be sure though, if you do
> attempt a key relearn that your battery is charged
> because if it dies in the middle of a learn it is
> possible to ruin the passkey module.As far as
> possible
> "common" causes of your original symptoms they would
> be : loss of vcm to cluster communications, blown
> guages fuse, bad vcm, or bad cluster. Those are
> about
> the only things that would cause the original
> symptoms. As far as the new problem you induced it
> could be a number of problems relating to the
> passkey
> module, bcm, vcm , wiring, fuses, or just simply a
> lost password. I hope this sheds a little more light
> on the situation,
> Phil
> 
> 
> 
> 		
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