Help Passlock Issue?

[xeroinfinity]

Originally Posted by Iflylow

I may be mistaken but I believe BCMs are programmed with the vehicle VIN, and there is no way to reset it. Once it determines that the VIN of the PCM does not match, it will not allow the car to start (or do anything else). Only a new BCM will work.

You are correct the BCM has to be programed by the dealershits, even a new(or used) BCM has to be reprogramed for the specific car its being installed in.
Also a bad BCM should trip the SVS light with a p1610 DTC or something close.

Here is the GM Tech info I have on the BCM curtisy of Bob Naylor.

SETUP NEW BODY CONTROL MODULE (BCM)

TOOLS REQUIRED
Scan Tool (Tech 2)

IMPORTANT:

Read this procedure carefully and completely.
The BCM will not function properly if the Setup New BCM procedure is not performed.
Perform the Theft Deterrent Re-learn procedure after successfully finishing the Setup New BCM procedure. If the Theft Deterrent Re-learn procedure is not performed after a BCM replacement, the following conditions may occur:
The vehicle will not be protected against theft by the PASSLOCK system.
The engine will not crank nor start.
Connect a Scan Tool (Tech 2) to the Data Link Connector (DLC) .
Turn the ignition switch on.
Select Diagnostics and input all of the required data when prompted by the Scan Tool (Tech 2).
Select BODY CONTROL MODULE.
Select SPECIAL FUNCTIONS.
Select New VIN and input all required data.
Exit back to the SPECIAL FUNCTIONS menu.
Select BCM REPROGRAMMING.
The scan tool will display DO YOU WANT TO SETUP A BODY CONTROL MODULE? At the prompt, select SETUP BCM hotspot on the scan tool.
The scan tool will display: NOW SETTING UP THE NEW BODY CONTROL MODULE.
When the BCM has been setup successfully, the scan tool will display: BODY CONTROL MODULE SETUP IS COMPLETE.
When the BCM Setup Procedure and VIN have been entered, proceed with the Theft Deterrent Re-learn procedure. NOTE: After the above procedure has been completed, personalization of the BCM defaults to a default setting. Inform the customer that the personalization settings must be set again.

Also If any of you have the sun roof, it can leak and run down the pillars right onto your fuse boxes which causes the BCM to become toast.

I just went through this on my GA GT , leakin sun roof and I thought it was fixed replaced the BCM(w/used one) and then it was toast too.
Though everything worked fine, the SVS light was on constantly. Replaced my drain hoses and now I'm dry and no SVS light.

But this whole passlock issue is none stop with GM vehicles.
As stated on the first page, ignition switch, lock cylinder, and or the BCM/PCM are the places to start looking. It is much more dificult to track down without the right equipment ie. Tech II scanner.

Good Luck!

[xeroinfinity]

Originally Posted by ponchonutty

PK2= Passlock 2 antitheft system. What's got me concerned is this BCM has Data Loss code B2958 in memory. Which usually means you have a bad BCM. If the BCM is acting up it'll cause the PK2 system from starting your car. Find the BCM and wiggle the connectors on it to see if that helps. You can also disconnect the BCM and plug it back in to see if that changes anything as well. You said you replaced the BCM so is this code before or after? Either way, you'll need to teach the BCM your car's PK2 code by doing the 10min on/off deal.

Not all serial data losses are due to a bad BCM.
Could be a wire shorted or loose connections, or even a low battery .
And can also be from the Ignition switch not sending data to the BCM or PCM for the PK2 system to operate properly causing a no start.

Here is another TSB on the BCM.

BCM - Security Lamp ON/No Crank/DTC's Set
Bulletin No.: 04-08-47-003
Date: August 31, 2004
TECHNICAL
Subject:
Security Light On, Engine Will Not Crank, Diagnostic Trouble Codes B2958 and/or B2960 (Repair Poor
Terminal Connections at Body Control Module)
Models:
2000-2005 Chevrolet Impala, Monte Carlo
Condition
Some customers may comment on an engine that will not crank. Others may comment on the security light
being on.
Technicians may find DTCs (diagnostic trouble codes) B2958 and/or B2960.
Cause
These conditions may have several different causes. In each case, however, testing of the BCMs (Body
Control Modules) replaced for these conditions are frequently found to be operating to specifications and are
believed to have been replaced needlessly. A change was made to the BCM hardware in February of 2003. An
updated BCM can be identified by a GMAN169 or higher number found on the BCM part label. This
hardware change was made to prevent the remote possibility that a BCM, built after the GMAN169 number,
could be the cause of these conditions.
Correction
The following are the likely causes of these conditions:
1. Damaged or loose/unseated terminals in these BCM connectors may cause a security light or no start
condition:
^ BCM connector C1 (24-way, pink in color), terminal B9 (white wire, circuit 1459)
^ BCM connector C1 (24-way, pink in color), terminal B12 (black wire, circuit 1835)
^ BCM connector C2 (24-way, grey in color), terminal A3 (yellow wire, circuit 1836)
Important: Use only approved tools for removal and testing of terminals. Do not use unapproved tools to
probe a terminal as this could cause damage. Use Probe Tool J 35616-6, from the J 35616-B terminal test
kit, to test the terminals in the BCM connector.
2. Check all the terminals in both BCM connectors, focusing on the three terminals listed above, for damage
and proper seating of the terminal in the connector. If no damage is noted, follow the normal SI diagnostic
procedures including clearing codes and attempting to duplicate the concern.
3. Always check for and clear all DTCs after recharging or disconnecting the battery. Attempt to restart the
vehicle only after all DTCs have been cleared. This will help prevent an unnecessary BCM replacement
due to false DTCs being set while servicing the battery.
4. A BCM should not be replaced when DTCs U1016 and/or U1064 have been set, even though the BCM is
turning on the security light. Diagnose and repair or replace components as directed by the diagnostic
procedures for these diagnostic trouble codes.
5. A current or history diagnostic trouble code B2958 in the BCM and a loss of battery voltage due to a
battery going dead or a battery disconnect may cause a no start condition upon recharging or reconnecting
the battery. Clearing the diagnostic trouble code will allow the vehicle to start.
6. The security light may turn on when the IPC (Instrument Panel Cluster) or PCM (Powertrain Control
Module) does not receive a state of health message from the BCM within a specified window of time.
DTCs U1016 or U1064 may set. Upon receiving the state of health message again, the security light will
go out and diagnostic trouble codes will go to history. If this happens frequently, the vehicle may exhibit
an intermittent or random flash of the security light.

[ponchonutty]

xero, that's some very good information. You know, we should some how make a sticky out of what I know and what you know for all GM owners to read since EVERY gm owner that's got a car with a pk2 system will face this issue.