Originally Posted by 8VETTE7

The BCM is not plug and play between years so you would need to identify the pin layouts between the two years and do some repinning of the cables to even stand a chance of making the newer BCM work in the 2000. probably could be done but would take a fair amount of time at a minimum.

The purple wire is part of the Column Lock Recall Service that was done by GM. They replace a SPST relay with an SPDT relay and splice into the purple wire . The purpose is to put a constant 12V in the "pin retract" direction of the lock motor. That is supposed to prevent the column from ever locking with the car under power.

You are getting the PULL KEY.... message because of this modification to the relay. (Same relay provides power to the lock motor for lock and unlock). Read this thread to see what is necessary to eliminate the message that you are getting:

http://forums.corvetteforum.com/c5-t...installed.html

Pay particular attention to post #15.

Originally Posted by 8VETTE7

Most common cause of the column lock symptoms is a weak or bad battery or loose or corroded battery connections including at the starter.

That is where I would start. The column lock electronics is going to fail if the no load battery voltage is 12.5 volts or less. No Load voltage is the voltage measured directly across the battery posts with the neg battery cable disconnected using a digital multi meter. Car will start with as little as 12.2 no load volts but the column lock electronics is NOT going to be happy. Since column lock function runs before the engine starts, voltage from the alternator once the engine is running is TOO LATE to help.

Does the column lock with NO KEY in the ignition? If not then something has been done to prevent it from locking. Get the GMVIS for the car and see if the GM Column Lock Recall Service was done after Jan. 2006. If so then the car has a small diameter lock ring that prevents the column from physically locking. If the recall was done before Jan 2006 then someone may have installed a CLB or perhaps an LMC5 aftermarket device.

If column LOCKS with no key in the ignition, I strongly recommend you get a CLB or LMC5 and install it. Once you go to a light weight (under spec) battery, you will constantly be having low voltage issues when the car sits for a few days and is not on a battery tender.

If you are going to get the car tuned by a tuner with either HP Tuners or EFI Live, then have the fuel shutoff speed set to a high number. If you don't you will end up getting stranded by the 2mph fuel shutoff that is SOP with the GM Recall Service. No tuning software except these two can set the fuel shutoff to a high number. 200 or 255 are good values to avoid getting stranded by the fuel shutoff speed.

Originally Posted by 8VETTE7

If the steering locks with no key in the ignition, there is NOT a CLB or LMC5 installed.

Recall done on an 04 Z where the column still locks means that the PCM has been programmed to shutoff fuel at 2MPH when the BCM thinks the column is locked after it has requested an unlock.

Causes for that MOST likely is the battery but a fried Column Lock Relay can also cause the symptoms. You can measure the NO LOAD voltage ( voltage across the battery posts with the Neg battery cable disconnected) and it needs to be greater than 12.5 volts for the column lock electronics to function correctly. Car will start with as little as 12.2 volts no load BUT the column lock system WILL fail so you get the messages, Column may not unlock and 2mph fuel shutoff may be set. Voltage after the car starts is too late as the column lock system runs BEFORE the engine starts...

You can try charging the battery fully and see if it will hold a charge. A good battery at full charge measures between 12.7 and 12.9 volts or more (no load). Battery voltage on the dash guages does NOT indicate the state of health of the battery. It indicates the state of health of the charging system. With engine running it indicates the output voltage of the alternator. With key on and engine off it has little meaning since many electrical systems are loading the battery.

Only way to know if the Column Lock Relay is good (your car should NOT have a GM K Harness) is to see if the battery being charged corrects the column lock symptoms or to bench test the Column Lock Relay. CLR is located in the passenger footwell to the left of the IPC fuse box and above the BCM (large silver box). The wires in the wiring base identify it as the CLR, 2 orange, 1 white, 1 green and 1 purple.

I suggest that you install a CLB to avoid this problem in the future.

Originally Posted by 8VETTE7

Does this car have a custom tune on it???

If yes then MOST tuners will set the fuel shutoff to a high number. That would explain the being able to drive without the 2mph fuel shutoff.

Are you certain that before this problem recently began that the column DID in fact LOCK with no key in the ignition???

If the column lock recall service was done to the car afterJan. 2006 then the variation of the column lock ecall service that was done may have been 04006C. That variation replaced the lock ring with the small diameter lock ring that is in automatics and the column no longer physically locks. Additionally if NO PREVIOUS variation of the column lock recall was ever done to the car, the 04006C variation does NOT include reprogramming the PCM to set the 2mph fuel shutoff. You can determine when the recall was done by sending an email to either of the following 2 Forum Vendors along with your VIN and ask for a copy of the GMVIS for your car:

dfichtner@fichtnerchevrolet.com Dennis Fichtner

gene@gmpartshouse.com Gene Culley

You will receive back a copy of the report by email. In the CLAIM HISTORY section of the report you can see all work done to your car at GM's cost (warranty, recall, etc) and the dates done.


If 04006C was not done and since the message "Service Column Lock" appears, the BCM sent an UNLOCK command to the lock motor but failed to get a response back to the command from the lock motor. Either the physical electrical path to or from the lock motor has failed (Two different paths) or the lock motor is hung up in the retracted position. If 04006C was in fact done then there IS a GM K Harness installed and that may have fried due to the low battery and would explain why the error message is displayed but neither the column is locked or the fuel shutoff occurred.

Determining exactly WHAT has been done to a car by either previous owners or by GM can be a frustrating effort. Sometimes it requires BOTH the GMVIS and physically checking...........