Can't Start My Car Because of the Passlock Security System

Key Points

  • Passlock sensor errors are preventing owners from using their cars.
  • Temporary fixes are a pain in the butt, but permanent solutions can get quite expensive.
A red SECURITY warning illuminated above the tachometer.
Posted on
Author
Scott McCracken
Tagged
#electrical #engine

Passlock is an immobilizer introduced by GM in many mid-to-late 1990’s vehicles. Immobilizers are “electronic security device fitted to an automobile that prevents the engine from running unless the correct key (or token) is present.”[1] Well, Passlock should be called the Great Immobilizer because not only does it stop thieves with no keys, it also stops owners with the right keys.

How do I know if my car has Passlock?

GM introduced many security systems – VATS, Passkey, Passlock, but if your GM has a key without a chip in it, chances are it’s passlock.

How is Passlock supposed to work?

Passlock uses a coded lock cylinder that essentially stops the engine from running until the proper key is detected. When the key is inserted into the ignition, a magnet on the cylinder creates a signal to the ECM (engine control module) that essentially says everything is ok to start and run.

What goes wrong with Passlock?

The short answer is there’s a problem with the sensor. Some have suggested that the pins in the system are “tin” plated and subject to oxidization over time. Others say their system is possessed by the devil and in need of an exorcist. I’ll let you decide which one sounds more accurate.

When the sensor defect starts, it usually presents itself as system fault code B2960. A red (or yellow) “security” warning light will stay illuminated and the engine will either a) never start or b) start for a moment and then shut down.

How to Fix Passlock for Chevy Vehicles

A temporary fix is to leave your key in the ignition, at the “auxiliary” position for about 10-15 minutes until the security light shuts off. When the light shuts off you can try to start the engine again. Rinse, repeat, and cry.

A more permanent solution is to either replace the ignition lock cylinder or bypass the sensor.

Replacement cylinder with new sensors can cost, with labor, as much as $450.

Bypassing the sensor will void any warranty, but since most of these vehicles are out-of-warranty at this point that might not be of any concern. NewRockies.com has a solution for how to fully bypass the PassLock system in GM cars.


  1. https://en.wikipedia.org/wiki/Immobiliser ↩︎

Generations Where This Problem Has Been Reported

This problem has popped up in the following Chevrolet generations.

Most years within a generation share the same parts and manufacturing process. You can also expect them to share the same problems. So while it may not be a problem in every year yet, it's worth looking out for.

  1. 1st Generation Avalanche

    Years
    2002–2006
    Reliability
    64th of 80
    PainRank
    19.22
    Complaints
    317
    Continue
  2. 2nd Generation Avalanche

    Years
    2007–2013
    Reliability
    56th of 80
    PainRank
    12.69
    Complaints
    373
    Continue Front 3/4 view of a Avalanche
  3. 2nd Generation Blazer

    Years
    1995–2005
    Reliability
    52nd of 80
    PainRank
    10.91
    Complaints
    611
    Continue
  4. 4th Generation Camaro

    Years
    1993–2002
    Reliability
    25th of 80
    PainRank
    2.55
    Complaints
    98
    Continue
  5. 3rd Generation Cavalier

    Years
    1995–2005
    Reliability
    58th of 80
    PainRank
    13.89
    Complaints
    1077
    Continue
  6. 1st Generation Cobalt

    Years
    2005–2010
    Reliability
    70th of 80
    PainRank
    31.78
    Complaints
    1054
    Continue Front 3/4 view of a Cobalt
  7. 1st Generation Colorado

    Years
    2004–2012
    Reliability
    48th of 80
    PainRank
    10.08
    Complaints
    378
    Continue Front 3/4 view of a Colorado
  8. 6th Generation Corvette

    Years
    2005–2013
    Reliability
    38th of 80
    PainRank
    4.9
    Complaints
    86
    Continue Front 3/4 view of a Corvette
  9. 1st Generation Equinox

    Years
    2005–2009
    Reliability
    74th of 80
    PainRank
    36.18
    Complaints
    1019
    Continue Front 3/4 view of a Equinox
  10. 1st Generation Express

    Years
    1996–2020
    Reliability
    15th of 80
    PainRank
    1.43
    Complaints
    74
    Continue
  11. 1st Generation HHR

    Years
    2006–2011
    Reliability
    63rd of 80
    PainRank
    18.7
    Complaints
    575
    Continue Front 3/4 view of a HHR
  12. 8th Generation Impala

    Years
    2000–2005
    Reliability
    79th of 80
    PainRank
    40.95
    Complaints
    3317
    Continue
  13. 9th Generation Impala

    Years
    2006–2013
    Reliability
    69th of 80
    PainRank
    28.86
    Complaints
    1217
    Continue Front 3/4 view of a Impala
  14. 5th Generation Malibu

    Years
    1997–2003
    Reliability
    68th of 80
    PainRank
    26.35
    Complaints
    2036
    Continue
  15. 6th Generation Malibu

    Years
    2004–2007
    Reliability
    73rd of 80
    PainRank
    35.26
    Complaints
    1224
    Continue
  16. 1st Generation Malibu Maxx

    Years
    2004–2007
    Reliability
    28th of 80
    PainRank
    3.14
    Complaints
    36
    Continue
  17. 5th Generation Monte Carlo

    Years
    1995–1999
    Reliability
    21st of 80
    PainRank
    2.42
    Complaints
    66
    Continue
  18. 6th Generation Monte Carlo

    Years
    2000–2007
    Reliability
    53rd of 80
    PainRank
    11.48
    Complaints
    547
    Continue
  19. 1st Generation Silverado

    Years
    1999–2006
    Reliability
    72nd of 80
    PainRank
    34.69
    Complaints
    2062
    Continue
  20. 1st Generation SSR

    Years
    2003–2006
    Reliability
    22nd of 80
    PainRank
    2.44
    Complaints
    14
    Continue
  21. 10th Generation Suburban

    Years
    2007–2014
    Reliability
    50th of 80
    PainRank
    10.7
    Complaints
    563
    Continue Front 3/4 view of a Suburban
  22. 2nd Generation Tahoe

    Years
    2000–2006
    Reliability
    57th of 80
    PainRank
    13.38
    Complaints
    419
    Continue
  23. 1st Generation Trailblazer

    Years
    2002–2009
    Reliability
    71st of 80
    PainRank
    32.88
    Complaints
    2158
    Continue Front 3/4 view of a Trailblazer
  24. 1st Generation Traverse

    Years
    2009–2017
    Reliability
    67th of 80
    PainRank
    23.09
    Complaints
    565
    Continue Front 3/4 view of a Traverse

OK, Now What?

Maybe you've experienced this problem. Maybe you're concerned you will soon. Whatever the reason, here's a handful of things you can do to make sure it gets the attention it deserves.

  1. File Your Complaint

    CarComplaints.com is a free site dedicated to uncovering problem trends and informing owners about potential issues with their cars. Major class action law firms use this data when researching cases.

    Add a Complaint
  2. Notify CAS

    The Center for Auto Safety (CAS) is a pro-consumer organization that researches auto safety issues & often compels the US government to do the right thing through lobbying & lawsuits.

    Notify The CAS
  3. Report a Safety Concern

    The National Highway Traffic Safety Administration (NHTSA) is the US agency with the authority to conduct vehicle defect investigations & force recalls. Their focus is on safety-related issues.

    Report to NHTSA