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Q: Service column lock ( Answered 5 out of 5 stars,   1 Comment )
Subject: Service column lock
Category: Miscellaneous
Asked by: bigmac200-ga
List Price: $100.00
Posted: 23 Dec 2005 11:12 PST
Expires: 22 Jan 2006 11:12 PST
Question ID: 609289
I have a 1999 Vette, with 84,000 miles on it. A daily user. The car is
really great shape. The car was backed into and some damge was done at
$1100. After the repairs were made the next day I went to start the
car and the "service column lock" warning came on.
Is the dangerous to drive and just what is the warning about. The
dealers in my area are the worst ever. So I need to know as much as
possible about this situation. Note, I am the second owner on the
vehicle. It was purchased with 4,000 miles on it.
Also, is there a recall that I do not know about?
Subject: Re: Service column lock
Answered By: webadept-ga on 23 Dec 2005 19:46 PST
Rated:5 out of 5 stars
Hi Mac, Season's Greetings. 

This appears to be a very common problem with Vettes of your year and
others. I found many sites that can help you with this, but the most
informative of these was on a Forum for Vette owners who created a
full thread area all about this problem. Here is a piece of the
information there, and the link to see the whole area.


" This is an attempt to compile all the Column Lock Information into
one place. If there are errors, please contact me so I can make
corrections. With all the recalls, there is a lot of confusion,
questions, anxiety, and threads. Hopefully this will be helpful to our
forum readers.

    * GM installed a Steering Column Lock mechanism on all 1997 - 2004
manual (MN6) cars and on 1997 to 2000 automatic (A4) cars
    * There is a GM recall for this problem on affected models and years
    * It is one of the most problematic issues that we C5 owners deal with
    * It can happen to you if you have a pre-2001 A4 without the
recall or CLB installed OR any year MN6 or Z06 car without a CLB
installed. Age or mileage makes no difference.
    * Low battery voltage seems to aggravate and sometimes cause
column lock failures

Q What is the symptom of failure?
A Your steering wheel will not unlock and the DIC will display an
error message "Service Steering Column Lock". Your owner's manual will
instruct you to have your vehicle towed to the nearest GM dealer for

Q What exactly causes this failure?
A When you insert your key into the ignition and turn it to the ON
position, the BCM (Body Control Module) sends a command to your Column
Lock Motor to "unlock" and then checks a status line to ensure that
the steering column is unlocked. If it gets the wrong status, it will
display an error message as mentioned above. It can be caused by ECL
(Electronic Column Lock) mechanism failure and occasionally by low
battery voltage, which sometimes confuses the BCM.

Q Can anything be done to unlock the steering column once it has locked up?
A Sometimes; turn the ignition OFF and REMOVE the key. Shock your lock
motor actuator assembly by jerking the steering wheel against the
stops. Re-insert your key and try again. Also, if your battery voltage
is low, charge your battery or replace it.

Q If my battery is discharged and I jump it to get the engine started,
the alternator is now charging shouldn't the column unlock?
A NO; The whole unlock sequence occurs before you ever turn your key
to start your engine. If the battery is too low, you will probably
have trouble with your column lock. Several folks have replaced their
battery and the column lock problem has never occurred since.

Q Does this problem affect both A4?s and MN6 vehicles?
A Yes; however if you have 2001 or newer A4 car, the ECL has been
removed or disabled.

Q What years are affected?
A Pre-2001 A4 cars and all MN6 or MN12(Z06) cars.

Q Is there any solution for this problem?
A Yes; have the recall done if you have an A4 car or install a Column
Lock Bypass (CLB) on MN6 & MN12 cars BEFORE the problem occurs. Once
it fails, you may not be able to fix it without GM repair."----

The website is the Corvette Forum

If you require more information than what they have complied on that
page, let me know the nature of your need and I'll see if I can find
it for you.


bigmac200-ga rated this answer:5 out of 5 stars and gave an additional tip of: $100.00
Perfect. I first had the old battery checked and tested. The rating on
the battery was fair. I decided it was time to replace it anyway. It
cleared the problem.
In addition to this I ahve made an appointment with the GM dealer in
the next county to check for the recall notice on the vehicle.

Subject: Re: Service column lock
From: mattdx-ga on 23 Dec 2005 11:47 PST
Hi bigmac200,

This thread in the Corvette forums seems to outline everything
surrounding 'service column lock'.

As it is you who knows all of the details, it would probably be better
for you to read through it, rather than me cite particular bits of it
that may have some relevance.  Saying that, much of the
information/adivce is conatained in the first post anyway.

From the sound of it, it doesn't seem that it is possible to even
drive the car when the column is locked, so I doubt it's safe!

Also, details of recalls are also available in the first post of that topic.

Hope that helps in some way,

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