Results 1 to 8 of 8

Thread: Code U1000 Security Light on No start. HELP!!!

  1. #1
    Junior Member
    Join Date
    Mar 2008
    Posts
    40

    Default Code U1000 Security Light on No start. HELP!!!

    So I go outside in the morning to turn on my car and nothing. The security Light goes on. I try to disconnect the batt and remove the ecm fuse. I put it back on and nothing. I hook up the scan tool and there is a code it U1000. So I use the tune tool to disable my vats and upload the tune to the ecm and still nothing. Is there anything I missed out on? Or any other trick out there? Guidance would be really appreciated thanks!!!

  2. #2
    Senior Member
    Join Date
    Aug 2007
    Posts
    126

    Default

    did you do a full reflash? If not try that, are there any body trouble codes, may be a bad ignition switch.

  3. #3
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    What had you done to the car prior to this morning (when the car was still working)...?

    U1000 means something like "Class 2 bus malfunction"

    Some module is hogging/abusing the serial bus (i.e. driving it exclusively, either pulling it down or up)...
    to pinpoint the offending module, pull fuses for each module until the bus starts working again.

    Or the bus is open...

    Or one of the modules necessary (PCM to run engine, BCM to validate startup) is broken and not communicating.

    What was the donor car that you got your PCM, harness and other stuff from...?

  4. #4
    Junior Member
    Join Date
    Mar 2008
    Posts
    40

    Default

    Nothing, I did a headers swap last week but it was running fine. I got up this morning to try and start it and nothing the security light is on. Its a 1999 ws6 6 speed with boltons. Original Pcm and harness, car has 59k on it. That's the only code that comes up, u1000. I'll try pulling fuses but wouldn't just disconnecting the battery do the same?

  5. #5
    Junior Member
    Join Date
    Mar 2008
    Posts
    40

    Default

    Quote Originally Posted by chevy052500hd View Post
    did you do a full reflash? If not try that, are there any body trouble codes, may be a bad ignition switch.
    wouldn't the vats disabled bypass the ignition switch? Yea I did a full flash I Always do

  6. #6
    Junior Member
    Join Date
    Mar 2008
    Posts
    40

    Default

    modules are $60 and $10

  7. #7
    Lifetime Member mr.prick's Avatar
    Join Date
    Nov 2006
    Posts
    3,195

    Default

    Make sure all your grounds are good.
    U codes are a bitch.
    512k RoadRunner Firmware 12.14R
    FlashScan V2 Bootblock V2.07.04 Firmware V2.07.22 EFILive V7.5.7 (Build 191) V8.2.1 (Build 181)
    LC-1 WBO2

    _________________________________________________

  8. #8
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    Quote Originally Posted by ls698ta View Post
    modules are $60 and $10
    $10 = PCM
    $60 = IPC (Instrument Panel Cluster/Controller)

    The PCM and IPC usually communicate (VSS, RPM, and a few other things)...

    The scantool can still connect with the PCM, right...?

    So it seems the PCM can't properly connect with the IPC... or it just discovered that it can't... either broken wire, broken IPC, or missing IPC.

Similar Threads

  1. Persistent security light
    By vortecfcar in forum RoadRunner Real-Time PCM Emulator
    Replies: 17
    Last Post: April 8th, 2012, 07:59 AM
  2. Check engine light/No code?
    By Brad-06-Dmax in forum Duramax 06 LLY / 06+ LBZ & LMM
    Replies: 9
    Last Post: January 14th, 2010, 04:25 AM
  3. 02 Yukon COS 02020005, Reduced power light, No Start
    By genericuserid in forum Gen III V8 Specific
    Replies: 0
    Last Post: June 4th, 2009, 12:32 AM
  4. HSV with imbedded security no start?
    By rally1 in forum RoadRunner Real-Time PCM Emulator
    Replies: 14
    Last Post: December 5th, 2008, 08:40 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •