Steering column lock - battery
The battery is new in my car, just replaced by the dealer, they checked the electrical system at the time and found everything to be normal. The steering column lock will work fine 5 or 6 times in a row then it won't work and it has taken anywhere from 10 minutes to 10 hours to self-correct/reset before the car will start again. I have been checking it (starting the car) every evening for the last few days without a problem, until this morning. I had a service appointment at my local Chevy dealer to look at the problem this morning, but the "Service Column Lock" DTC came up and the car would not try to start. My wife kept trying it after I left for work, the car started about an hour later.
I finally got the car into the dealer for service, had to tow it in. The dealer diagnosed it as a steering column lock failure, ordered a new part, the wrong part came in as this lock is not shown in their parts catalog (the lock for a C5 is shown). They were finally able to get the correct part number from Delphi and get a new lock. The new lock worked for less than 10 drives when it froze up again and left me stranded. I got the original lock from the dealer, took it apart and found the problem. The lock is mostly made of poor quality plastic and the actual pin that engages the locking ring is moved in and out via a worm screw that passes thru a block that trips a microswitch. The plastic worm screw binds in the plastic block, the drive motor current starts to rise and the computer detects the overcurrent and stops the process and issues a "Service Column Lock" DTC.
A Steering Column Lock Simulator for a C5 will not work on this lock because the signal from a C5 back to the computer is only open or closed circuit. The C6 is looking for a certain resistance when the steering column lock is engaged then a different resistance value when the lock is disengaged. I was able to build a working prototype steering column lock simulator for my C6 and am currently looking for the GM connector so that I can build a few C6 column lock simulators.