Hey all, I’ve been having some trouble with my 2001 l200, recently my security light came on again and then my battery died, so I jumped it and it worked until I turned it off. Had to jump it again and now the security light is just blinking with my car being able to crank but not start the engine. I haven’t found much help online that works as I tried the 30 minute cycle with the key in the acc position but it did not end up working for me, the security light would stop blinking and remain on and then disappear but after three it attempts it would still not start. I tested my battery at autozone and the charge is at 78% and is relatively a year old in a couple days. I don’t have a key fob either but if there’s anyone that can help me out I would greatly appreciate it.

 

Key needs to be in "on", not ACC, position.
Please confirm which of the above you actually performed.

 

After you resolve your battery issue, you will need to do the proper sequence of the 30 minute security relearn 3 times. It has to be performed perfectly or you get to start over. A new battery will not survive without a quality charger attached and turned on. A maintenance charger is not adequate for this type of shop work. Have you figured out why your battery went dead?

 

100% agree on the charger aspect.
Because the ignition will be on for 30 min continuously without the alt charging the battery, ithe battery charge gets sucked down quickly. If the ecm and bcm do not receive sufficient current at the correct voltage, they will not operate properly and the relearn will fail. And you're trashing your battery.

 

I had preformed “on” and not “acc” after further inspection. Can one of you explain the steps for the security relearn so I can make sure I’m doing it right?Also with the battery I think one of the lights got switched to on when I was moving to a new place.

 

See this sticky from the general tech section of our forum

(GM)Passlock II reset procedure

Note: when you turn the key off for 5 seconds, when you turn it to crank it needs to be one motion from off straight to crank. Do not stop in any intermediate position. If you stop in the on position before getting to Crank, then you are literally going from on to crank instead of off to crank. That is a deviation from the procedure and it likely will fail. Yes I understand you are going through the on position to get to Crank. However, that's not the way the procedure is written. It is written to go straight from off to crank.

Moral: follow the procedure EXACTLY as written and you, like tens of thousands of others, should be able to have your vehicle relearn passlock, start, and drive. Just like a car should.

And put a real battery charger on the battery that can keep up with 30 minutes of key on battery drain. Just because the dash lights up does not mean the ECU is functional, the BCM is functional, blah blah blah. I've suggested to folks that don't have a battery charger to simply hook up a running vehicle and use jumper cables such that the alternator output is a partially going to both that car's battery and to your battery. Rather non-optimal as it is equivalent to a fast high current charge but it should provide enough current. wastes a ton of gas but sometimes you have to do what you have to do

Please post back with results.​​​​​​

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If your 2001 has daytime running lights apply the parking brake to turn them off during this procedure.