Custom-tuned, '01 MN6 Coupe:

I had the GM recall done a LONG time ago (8 years ago, I think), during which the locking ring was completely removed. Removed the inline Corvettes of Houston (I think) CLB then, too. No issues for years. About 2 months ago, I started getting a Service Column Lock message. I am not having any fuel shut-off issues, or anything else related to the message, so I am wondering if this is a reminder message for some kind of mileage-related service. I have no codes, as read with a scanner.

Does anyone know how to turn this message to turn off? For example, is there a reset procedure similar to the Change Oil light, or something?

 

Cutom-tune was done in 2004, long before there was even a ring-switching recall. I actually drove 100 miles to a specific dealership to have the recall done because the Service Manager is a C5-owning member of this forum, so he knew what and what not to do, given my custom tune.

That said, while I am pretty sure the custom tune did not touch my fuel shut-off, it is possible, but not likely, that the dealership downloaded my cutom-tune and applied the high-mph fuel shut-off mod to my tune, as I'm pretty sure they don't want to have anything to do with any potential liability that might come along with going anywhere near my custom-tune, you know what I mean?

I am mentioning these details because I am not experiencing a fuel shut-off that I would think a relay would trigger. Am I wrong here?

While I would think a low load capacity of the battery would also trigger a fuel shut-off, I will check it as you advise, nevertheless.

And, if my logic is flawed here, please feel free to chime in with more thoughts.

FWIW, but not to flaunt abilities, I write software which happens to contain many "If-Then" statements, and "Case" logic, so following logic flow is something I can easily handle, if any is forthcoming.

 

Thanks for the info. It's too bad that GM never really did get the column lock issue resolved on the MN6 cars.

 

This applies to my situation. I avoided all the early recalls because after researching each of them, I could tell they wouldn't really work. Last one was best. In hindsight, I wonder if I should've not sold my CLB, and kept in there for good measure.

Understood, thank you for the details.

Believe me, if I saw anything else, I would have said so, so I am pleased to clarify that I see only the "Service Column Lock" message.

Do you know the harnesses under the battery that's comprised of 742 wires, 211 of them which are all black and of the same gauge? I previously had a mouse chew several of those black wires, which resulted in a no-start from severing a fuel pump wire. I rectified that with a shotgun, followed up by painstakingly diligent soldering. Do you have any idea how hard it is to solder back together multiple wires in that mess of spaghetti wires in the confines of the under-battery compartment, let alone try to figure out which black wire goes to which? It was a nightmare, to say the least. I was kidding about the shotgun, I used the more inhumane rat trap to make sure he/she got the point.

Funny thing (well, not so funny for me) is that I went down to my garage to check the battery load, and got sidetracked by a bad fuel pump in my K1500. Dropped the tank, pulled the pump, went to the store, and returned with the new pump to find that the new pump requires a splice retrofit of the harness on the car at the pump. How I wanted to use shrink tubing on the splice, but ended up deciding I was too close to the fuming gas tank to attempt it.

I will post back my cold load findings on my C5 battery when I get to it, likely tomorrow afternoon. Thanks again.

 

First, I should have done the following in the reverse order, but it did not dawn on me to do so (you'll understand why I say that after reading my results).

1) Tested the battery with negative lead disconnected. It read 12.26 volts. Reconnected the battery.

2) Put the key in and turned the ignition to the "On" position. Indeed heard the column lock mechanism operate normally. Given the information you shared, I was caught completely by surprise when the "Service Column Lock" message did NOT appear. In fact, I repeatedly reomved the key/turned acessory power on and off, fully expecting the disappearance of the message to be a total fluke, since I've been living with it for months now.

3) Turned the ignition off, then started the car normally. Still no "Service Column Lock" message.

While not necessarily a completely indicative test, by any means, it seems to me that 12.26 volts is enough voltage for the column lock system to function properly. It is entirely possible that this whole time (2 months, for me), my BCM simply needed a "reboot". This is why I wish I would have approached this more methodically and listened for the lock mechanism before disconnecting and reconnecting my battery. For example, if I had listened for the column lock operation first and not heard the mechanism move, and then disconnected/reconnected the battery and heard the mechanism move, we would be able to deduce that a "reboot" was all I needed, and may be what others who encounter this might try as part of the course of troubleshooting this gremlin. After all, the BCM is a computer, and computers of all sorts require reboots every so often. ;-) Maybe the next person who has this same issue will read this message and try the steps in the reverse order, and report their findings.

Out of curiosity, 8VETTE7, how did you come to determine that a no-load voltage less than 12.5 would cause the column lock system to fail? Was that from your own experience, or did you read that in a white paper detailing this specific implementation into the design of the column lock system? I am not trying to be argumentative, or anything, in fact, it was your information that helped be resolve my issue. So, please know that I'm only asking with the sincere hope that us thinking this through might help us pool our thoughts which in turn help our brethren and ourselves more systematically approach a potential resolution if we find ourselves having to troubleshooting this issue in the future. Here's what I mean:

After what I suspect was the "reboot" that resulted in my "Service Column Lock" message going away, I started thinking about what you said regarding a good, fully charged battery reading 12.7-12.8 with no load. Ok, but, if you sit in your car for any "decent" period of time with accessory power on, say listening to the sound system, or using any battery power for that matter, like you would with the door open while cleaning the car, or whatever, it would stand to reason that someone (more likely thousands, or more, people) would do something along these lines long enough for a battery's power to drop a bit (and that happens sooner than many people would think). Considering the fact that accessory power (key in "on" position, but car not running) has been a standard function in EVERY car for many years, I would think that GM would expect people to do this for periods long enough for battery power to drop, and a drop in voltage from 12.7 to 12.5 is really not unreasonable to expect. In fact, I can imagine that this is quite a common occurrence.

Now, if GM had intentionally designed the column lock to only operate properly at 12.5 volts, that would have been totally impractical, if not completely idiotic. In fact, that would pretty much guarantee that every single owner of a car with this system would find themselves in a column-lock-related predicament at one time or another, and quite likely MULTIPLE instances of such a predicament, you know what I mean?

I am by no means a certified auto-electronics technician, but I would think it takes more power to turn over an engine than it does to complete the operation cycle of the column lock. I guess what I am leading to here is that 12.5 volts seems like an awfully high requirement to be expected to consistently maintain in real-world practice (given a full charged battery is 12.7 volts), in order for people not to become stranded due to column-lock-system failures, when battery voltage less than that will turn over an engine.

Come to think of it, I don't remember ever encountering such a problem over the many years I've owned my particular C5, even before I had Recall #4 done. I also recall going through several charging procedure cycles with a wall-charger to "milk" more life out of a previous battery that was obviously dying, until I got around to replacing it, which I would think others would do, too. And, even then, I never experienced a problem with the column lock.

Just thoughts.

Now, if it turns out that the column lock system was indeed spec'd to operate properly at a minimum voltage requirement of 12.5 volts, and I simply got lucky (or the message returns in short order due to my 12.26 volt battery), then I guess I'd have no choice but to be another one to jump on the GM-bashing bandwagon over designing the column lock to specs that can only hope to be maintained in a perfectly controlled environment.

Regardless of what we might surmise from my exercise in verbosity, and quite possibly flawed logic to boot, I extend my sincere thanks to you for taking the time to help point me in the right direction in resolving my particular issue.