a PASSlock theft-deterrent system

Last night, my 2004 Impala wouldn't start. The key turned in the ignition, but no turnover. The yellow engine light on the dashboard appeared followed by "security" and "service engine soon" in the message box. I tried the 'lock' and unlock' button numberous times, manually locking and unlocking the doors with the key. I also tried starting it with another spare key. The exterior and interior lights worked as well as the power windows and radio. It doesn't seem to be the battery. I also waited extended periods of time between each try. At the moment, it is being towed to a dealership. My guess, concuded from the manual and neighborhood mechanic, is that the security system was tripped and the fuel and engine are locked up. Has anyone experienced this? If so , any advice?

Mine is having the same problem.

I found this.

No-Start or No-Start/No-Crank complaints
can occur for multiple reasons. However, one
of the reasons can be a shorted Class 2 bus.
Vehicle Theft Deterrent systems utilize the
Class 2 bus to communicate security
information between various controllers. For
instance, the BCM will get information from
the Passlock module and then communicate
with the PCM to allow or disallow fuel
delivery and/or starter enable.
When the Class 2 bus is shorted to either
ground or battery voltage, the controllers are
unable to communicate with each other. This
is because the voltage on the line is held
static at either ground or B+. The Class 2
message toggles the voltage on the bus
between 0 and 7 volts, but when the bus is
shorted, the toggling cannot take place.
Because the voltage remains static at either
ground or B+, the Class 2 message can't be
sent or received.
Without these Class 2 messages being
sent and received, the PCM won't get the
proper security messages which would
normally enable fuel and/or starter enable
and the customer will have a No-Start or No-
Start/No-Crank complaint.
TIP: If the problem is intermittent,
remember to search for the U1300 - Class 2
Data Link Low, and U1301 - Class 2 Data Link
High--in "History". This will help determine the
source of the problem.
– Thanks to Mark Harris

So....this mean what..sorry but umm do I just take it somewhere or what

This is from a GM site.

It means that this condition can be caused by a broken, grounded, or shorted wire coming from the passlock system on the starter key lock.

The "U" numbers it mentions are wire connectors for that system and are listed on a schematic.

If you are not proficient at searching down wires and testing the with a DVM then I guess you will have to take it "somewhere".

Ahh...i see...looks like I will have someone look at it...thanks