I have a 2001 Monte Carlo LS and here is my problem. I came home from work and the next morning I went to start my car and it would not start. The motor would not turn over just the dash lights came on even the horn worked but no radio lights came on so the battery had a charge. I went ahead and changed the battery and the car started right up. The next morning I went to start the car and it did the same thing again. The battery has a full charge but the car won't turn over. I removed the positive cable and put it back on and the car started right up but a little while later it did the same thing as before. I had someone replace the positive battery cable thinking it was a bad cable and it still does the same thing after about 30 minutes sitting. I'm hoping its not the passlock key cylinder that is causing this cause I just don't have that kind of money laying around to fix it. Any help is appreciated . Thanks inadvance. Keith

 

 

If it was the passlock you would be seeing security lights flashing.

How's your starter? You can sometimes go to a place and have those checked out for free.

 

I had a similar issue on my Monte, it turned out the post on the battery had a short in it, i replaced the battery and it never happened again...the odd part was the battery tested fine,and all my light's worked, just wouldnt start...

when i removed it the last time i could pull the terminal off the battery and put it back on...so there had to be a short in there..

 

If it's the Passlock, while the key is turned on, it'll flash "security" three times then "battery". IF it does that, leave the key turned to "on" for ten minutes until it quits flashing, then turn off and start.
BUT if the radio is NOT working, it's probably not the Passlock. Everything worked on mine except it would not start, no click, no attempt to start, except all lights, radio that sort of stuff worked.

 

Update, I took it to the local Chevy dealer and they said the passlock sensor was bad and that the whole key cylinder had to be replaced. I said fine to go ahead and change it out. I called to see if it was ready and now they are saying that they are having trouble reprogramming it.

 

UPDATE #2
I found out why they were having problems with the reprogramming, I just got a call from my dealer and I need the BCM replaced in addition to the passlock key cylinder. I was told the total cost is about $750 plus WV state tax. OUCH!

 

Final update; Went to pick up the car and got in it and noticed that the A/C was blowing hot air and check engine light was on. (Now I'm pissed to the max) They had my car for a total of 6 days and they can't see that the A/C wasn't working and the check engine light is on? This was late friday afternoon so I took the car home and was told to return it on Monday moring so they could find out what was causing this. Turns out that the "new" BCM they put in the car was shorted out which kept my A/C from working and now the car is running perfect again.YIPHEEEE

 

Sucks that they didn't check that everything was working properly before turning your car back over to you. Especially since it was on a Friday!

Glad all is well and it's back where it belongs!

 

That is exactly what I told them. They even tried to tell me that there was NO way my A/C was working properly when the car was dropped off because it was 1.5 lbs low on freon. I laughed at that claim and told them it worked perfectly and blew ice cold air when the car was brought in and since its not working now tell me exactly how you were able to determine that its low on freon when the compressor wouldn't even turn on. Also the said it was possible I had a leak and it was leaking out. Needless to say after they put the 2nd "new BCM in the car that it started working without any problems. If it was low as they 1st said the compressor would be constantly kicking on and off which it does not do.