Silverado Passlock Security Problem

[Nanker]

I have a 2001 Silverado V6 5-speed that I purchased water-damaged. I
have the engine working now after replacing quite a few parts, but I'm
now having a problem with the Passlock Security system. Every time I
start the engine, it will display a security warning on the dash and
the engine will shut down after a few seconds. I have tried to perform
the 'learn' procedure which is described in the service manual as
follows:

- Turn on the ignition
- Attempt to start the engine and then leave the key to On
- Wait for 10 minutes and then the security indicator on the dash
will turn off
- Turn off the ignition and wait 5 seconds
- Repeat the above steps 2 more times. The vehicle is now ready to
relearn the Passlock Sensor Data Code on the next engine crank.

I've tried these steps, but I don't know what the Sensor Data Code is
that is described above. Is there any way to get around this problem
so the engine will run successfully - I'm willing to use the vehicle
without the security system installed if there is any way to disable
it so the engine will function. Any suggestions would be appreciated,
as now the vehicle is just sitting in my driveway. Thanks in advance.

[Robert Hancock]

I think that after you do that, it should just start the next time you try.
If it doesn't, most likely there's something else wrong. In that case, you'd
likely need a Tech 2 scan tool to diagnose it.

What parts did you replace exactly? The BCM and/or PCM?
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from ***@nospamshaw.ca
Home Page: http://www.roberthancock.com/

Post by Nanker
I have a 2001 Silverado V6 5-speed that I purchased water-damaged. I
have the engine working now after replacing quite a few parts, but I'm
now having a problem with the Passlock Security system. Every time I
start the engine, it will display a security warning on the dash and
the engine will shut down after a few seconds. I have tried to perform
the 'learn' procedure which is described in the service manual as
- Turn on the ignition
- Attempt to start the engine and then leave the key to On
- Wait for 10 minutes and then the security indicator on the dash
will turn off
- Turn off the ignition and wait 5 seconds
- Repeat the above steps 2 more times. The vehicle is now ready to
relearn the Passlock Sensor Data Code on the next engine crank.
I've tried these steps, but I don't know what the Sensor Data Code is
that is described above. Is there any way to get around this problem
so the engine will run successfully - I'm willing to use the vehicle
without the security system installed if there is any way to disable
it so the engine will function. Any suggestions would be appreciated,
as now the vehicle is just sitting in my driveway. Thanks in advance.

[Bobo]

The theft deterrent system has been incorporated into the body control
module (BCM). The theft deterrent is provided in order to prevent the
vehicle operation if the correct key is not used in order to start the
vehicle. The ignition key turns the lock cylinder. The cylinder rotation
produces an analog voltage code in the PasslockT sensor. This voltage code
is received by the BCM. The BCM compares the voltage code to the previously
learned voltage code. If the codes match, a class 2 message is sent from the
BCM to the powertrain control module (PCM)/vehicle control module (VCM). The
message enables the fuel injectors

That's a little snipper straight from the manual.. I do not know of any way
to bypass it... you need to have the BCM awake and functioning... maybe you
haven't finished putting the rest of the dash back together???
The system includes the PCM,BCM, and the passlock housing which is part of
the ignition cylinder... If you want I can send you almost anything you
want, but the diagnostics are useless without a scan tool, and I think it
has to be a TECH II , dealer equipment... You can do some voltage
checks.... oh ya the BCM is the plastic module directly under the column...
3 plugs...Could this have gotten wet ??? Bobo

Post by Nanker
I have a 2001 Silverado V6 5-speed that I purchased water-damaged. I
have the engine working now after replacing quite a few parts, but I'm
now having a problem with the Passlock Security system. Every time I
start the engine, it will display a security warning on the dash and
the engine will shut down after a few seconds. I have tried to perform
the 'learn' procedure which is described in the service manual as
- Turn on the ignition
- Attempt to start the engine and then leave the key to On
- Wait for 10 minutes and then the security indicator on the dash
will turn off
- Turn off the ignition and wait 5 seconds
- Repeat the above steps 2 more times. The vehicle is now ready to
relearn the Passlock Sensor Data Code on the next engine crank.
I've tried these steps, but I don't know what the Sensor Data Code is
that is described above. Is there any way to get around this problem
so the engine will run successfully - I'm willing to use the vehicle
without the security system installed if there is any way to disable
it so the engine will function. Any suggestions would be appreciated,
as now the vehicle is just sitting in my driveway. Thanks in advance.

[Nanker]

Thanks for the responses.

The BCM has been replaced, and the vehicle was taken to a mechanic who
did a scan that supposedly reset the BCM. I've taken the vehicle to
other mechanics who have been unable to start it successfully as well.

Since the security system is controlling the fuel injectors, would it
be possible to bypass the security system (assuming I can get the
wiring schematic) and apply power directly to the fuel injectors?
Having a functional vehicle is more important than having this
security system. Hopefully I can find the schematic and this is
possible.

Thanks again.

[Bobo]

There is no way to bypass it that I know of... The BCM doesn't take away
power or anything, It has to see a valid passlock code before it will send
an encoded password to the PCM via the class 2 data line.... I know of no
way to mimic the password.. You may try some kind of stolen car web site or
something???? lol
If you have a mechanic who can reset????? the bcm then he should have been
able to diagnose where the problem was.I can send you the schematics, but
you have to start with the simple stuff... do a data check... does the bcm
send a state of health message along the class 2??? does it read a valid
passlock voltage?? It's actually simple with a Tech 2.Does your mechanic
have access to one??? I will try and send you the schematic and/or pinouts
of the bcm.. I would check all the powers and ground... Hopefully it's a
simple problem...Bobo

Post by Nanker
Thanks for the responses.
The BCM has been replaced, and the vehicle was taken to a mechanic who
did a scan that supposedly reset the BCM. I've taken the vehicle to
other mechanics who have been unable to start it successfully as well.
Since the security system is controlling the fuel injectors, would it
be possible to bypass the security system (assuming I can get the
wiring schematic) and apply power directly to the fuel injectors?
Having a functional vehicle is more important than having this
security system. Hopefully I can find the schematic and this is
possible.
Thanks again.

[bhalsdorf]

replying to Bobo, bhalsdorf wrote:
As far as I know there is no way to reset a BCM. It would have to be replaced
and flashed by a dealer in order to work properly. And then the relearn for
the ignition key needs to be done.