Chevy Impala 2004 Passlock problem

  1. Welcome to GM Inside News Forum – General discussion forum for GM

    Welcome to GM Inside News Forum - a website dedicated to all things GM.

    You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, Join GM Inside News Forum today!
     
+ Reply to Thread
Results 1 to 10 of 10

Thread: Chevy Impala 2004 Passlock problem

  1. #1
    Walking
    Join Date
    Mar 2013
    Posts
    2
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Chevy Impala 2004 Passlock problem

    Hi guys,new here, so i bought an Impala 2004 base model wich has a problem with the Passlock.the owner try to fix it buy replacing the ignition swicth from a Junk donor but, didn't work.He also replace the BCM from the same donor but didn't work aswell. he was tired of working on the car so he sold it to me. Anyway,so now the car wont start or even crank and the dreaded security symbol flashed in the message center! so i took my Genesys scanner to see if theres any DTC's and i got a full list of DTC's in the Historic only and i found that the scanner wont found the PCM and the Air Bag module, its sa that those are not present.here the DTC's that i found

    U1000
    U1016
    U1255
    B1478
    B2602
    B2618
    B2650
    B2655
    B2960
    B3127
    B3128
    B3132
    B3137
    B3138

    the three first are related to loss of commucation with PCM but remember those are only in Historic! so now im stuck and i dont want to replace a part that is not the culprit i wanna do a good diagnosys since i'm actually a student in automotive mechanic!

    oh and i found out i have no chime at all and the power windows dont work! and i also use the original BCM for the car


    if you have some info for me feel free to reply thanks guy

  2. Remove Advertisements
    GM Inside News
    Advertisements
     

  3. #2
    SX3
    SX3 is offline
    3.6 Liter SIDI V6 SX3's Avatar
    Join Date
    Dec 2010
    Location
    Texas
    Posts
    1,212
    Thanks
    35
    Thanked 53 Times in 36 Posts

    Re: Chevy Impala 2004 Passlock problem

    The way the passlock works is a chip inside the key that gives a signal to the passlock module on the ignition switch. That signal is sent to the BCM that checks to ensure that code is correct before it sends the ECM a different signal through a different set of wires to check the VIN number on the ECM and BCM match. Once the VIN match is done it allows the car to run properly.

    I'm not a 100% sure of the wiring of your vehicle since I'm used to the newer system on '06+ Ecotecs that I've had to troubleshoot. But if you aren't getting power to the starter to crank it seems you have electrical issues before computer issues.

  4. #3
    6.2 Liter LS9 Supercharged V8 MrCritical's Avatar
    Join Date
    Aug 2008
    Location
    South Of The North
    Posts
    6,362
    Thanks
    541
    Thanked 255 Times in 146 Posts

    Re: Chevy Impala 2004 Passlock problem

    First things first.

    Are we talking about the ignition switch or the ignition key cylinder?

    Secondly, there was probably nothing wrong with the original BCM. Where is it now? Can you get it back? The original problem was most likely the key cylinder. If you're not familiar with passlock and don't want to replace parts that don't need replacing, your fastest, best, and cheapest bet is to get to someone who is trained on the Passlock system.

  5. #4
    4.4 Liter Supercharged Northstar sonjaab's Avatar
    Join Date
    Apr 2003
    Location
    Syracuse-Alexandria Bay NY-Daytona
    Posts
    2,852
    Thanks
    20
    Thanked 22 Times in 18 Posts

    Re: Chevy Impala 2004 Passlock problem

    YUP............Critical is correct. Changed ignition switch, different transponder key, swapping
    the BCM, Passlock warning lights just asking for mucho no start/power issues!

    Best off biting the bullet and sending it to a GM dealer and his Tech 2 machine for a hookup
    and reprogramming and busting out yer wallet!

    Sorry no homebrew fixes with that passlock system !

    IF it was a late 80s early 90s GM VATS system we have a simple homebrew by-pass for
    that bad boy.
    Last edited by sonjaab; 03-31-2013 at 09:21 PM.

  6. #5
    Walking
    Join Date
    Mar 2013
    Posts
    2
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Chevy Impala 2004 Passlock problem

    like i said, i have put back the original BCM, and on the Impala,when the Passlock have problem,it block the car to start AND even crank, but there is some weird thing like i said,the scanner tell me that there is no PCM present and air bag module,there is no Chime or what so ever ,ALL power windows dont work. the Radio work well and it is not even Locked, all the light work,the doors lock too. i've found an TSB wich thy tell that the connector terminal for the BCM can be damaged or loose and can cause all the problem above but they seem fine.so anyway i'll wait t'ill tuesday i will ask my teacher ,he was a master Tech at a Pontiac dealership so


    thanks guy

  7. #6
    6.2 Liter LS9 Supercharged V8 MrCritical's Avatar
    Join Date
    Aug 2008
    Location
    South Of The North
    Posts
    6,362
    Thanks
    541
    Thanked 255 Times in 146 Posts

    Re: Chevy Impala 2004 Passlock problem

    When you disconnected the BCM you lost the program (which tells it there is no PCM).

    Once again are we talking the ignition switch, or the ignition key cylinder? They aren't the same thing.

    If you have the original PCM back in, it still will have to be reprogrammed, and you'll still have to find the problem (probably the key cylinder, not the ignition switch). But in some cases the switch has been bad as well. This is deep water if you aren't familiar with PassKey.

  8. #7
    2.4 Liter SIDI ECOTEC
    Join Date
    May 2012
    Location
    St Peters, Mo
    Posts
    112
    Thanks
    1
    Thanked 11 Times in 10 Posts
    My Ride
    Lone Star Skipper Sea King 35

    Re: Chevy Impala 2004 Passlock problem

    This one was a little hard to follow. Different terms being thrown around. Passlock, and Passkey are two quite different systems. An '04 Impala does not have a key with a transponder. Security issues on this system are often difficult to pin down. Trouble codes rarely are conclusive, and often tell an inaccurate story. Because of that many shops begin by replacing both the lock cylinder and ignition switch. If problems persist then normally a fresh BCM will solve it. The ONLY way a BCM can function correctly is if it is programmed for the vehicle it is being installed in. That's the exact path I went down with my '01 MC.

  9. #8
    3.6 Liter SIDI V6 swagled's Avatar
    Join Date
    Feb 2011
    Posts
    1,191
    Thanks
    46
    Thanked 47 Times in 31 Posts
    My Ride
    2014 Cruze Diesel

    Re: Chevy Impala 2004 Passlock problem

    There are also people who just say "the heck with it" and bypass the security.
    http://newrockies.com/
    http://www.fixpasslock.com

  10. #9
    2.4 Liter SIDI ECOTEC
    Join Date
    May 2012
    Location
    St Peters, Mo
    Posts
    112
    Thanks
    1
    Thanked 11 Times in 10 Posts
    My Ride
    Lone Star Skipper Sea King 35

    Re: Chevy Impala 2004 Passlock problem

    Even better solution!

    The one from Newrockies looks like the ultimate solution since it will work even if the BCM is acting up.

  11. #10
    Walking
    Join Date
    Sep 2013
    Posts
    1
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Chevy Impala 2004 Passlock problem

    I suffered through multiple no start conditions associated with the security system. As Larkbill notes, the newrockies bypass system has worked for me. been in a month and the car now starts when I want it too. A nice feature. Can't see what good the Passlock system is to anyone. I can live without it. Only person it kept from taking the car is me, the owner. A straightforward, if TIGHT, install.

  12. Remove Advertisements
    GM Inside News
    Advertisements
     

Quick Reply Quick Reply

Register Now

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Powered by vBadvanced CMPS v4.1.2