I finally found an SS in a my price range. After a month the security light would stay on some mornings on my way to work. The car started fine, but the light would stay on. Then every couple of days the light would come on and stay for the trip (distance didn't matter 1mile or 100miles). Then it wouldn't come on for a week or 2. Finally an "expert" online told me it was a PassLock issue and to reset the system by turning the ignition on for 10mins then off, then back on for 10mins, then off and a 3rd time for 10mins. Then another reset would be to lock the driver's door with the on door switch, get out and unlock it with the key to reset. Now my car has gone crazy. Not only does the security light come on, so does the service vehicle soon light. Sometimes the keyless remote will unlock the doors other times it only turns the dome light on and I have to use the key to unlock the door. Then when I'm seated the lock/unlock switches don't work at times. Then I have to wait a few seconds after turning the key to "on" before trying to start. When the dash lights finally come on sometimes it starts other times, nothing. After a few tries it eventually does start. Then the dome light randomly comes on if in Park. A few times, not a sound when unlocking the door, getting in or even putting the key in the ignition, but when turning it to start, the alarm goes off and I have to use the remote unlock button to turn off the alarm. Now that is an attention getter first thing in the morning. Once the lights came on, and the horn was a constant blast (not the pulse blasts the horn is supposed to sound when alarm is activated). Such odd random things happen at start up, like a gremlin crawled up in it somewhere. After starting, it runs fine, I can drive over 4hrs straight without any issues at all, but as soon as I turn it off it is the same hassle at start up. The theft and personalization system through the stereo is even strange. I can program it any way I want, but as soon as I turn the car off, it goes back to default settings. Please help.

 

You might have a BCM starting to fail

 

Hi `Adam,
Sorry to read about the problems you are having Is it throwing any codes ? If so, what codes ? How many miles on your Monte Carlo ? If you haven't had your codes read, take it to most any auto parts store & they will check them & give you a print-out....Good Luck..
If you would like the MCF Mod's to come to Carlolina to remove the demon, We charge a modest fee of $1K + expenses and the testing of your Monte for about a year...
We do have specials `if you are interested...
..`Demon Go back to Dodge where U came from lol

Seriously, I hope one of our expert tech members can give you some adivice/help ~> Good Luck

 

108K Miles....I did have it scanned as soon as I saw the "Service Vehicle Soon" light was on. No fault codes came up, the scan came up empty and said that it passed. That lead to another odd issue. The light is on + No fault codes = unable to reset anything to turn the light off. Even disconnecting the battery for an extended period didn't change anything.

 

After looking online, I have been leaning toward a bad BCM. I've looked into what that would require and although the part itself is not expensive and not too difficult to get to, I'm uncertain about the reprogramming. I know how to reprogram the keyless entry and the personal settings, but it is the reprograming (relearning) the TDS by way of a dealership or shop with the computer and needed software. Since everything is pointed towards the alarm option causing the problem with the BCM, if I were to grab a BCM from a Monte in a junk yard that did not have the factory alarm when originally purchased, I'm wondering if I could use it and not bother with the alarm and then TDS relearn at a garage wouldn't be needed and my mutiple problems may be fixed????

 

BCMs are picky, and they need to be programmed by someone with a Tech-2.

If you go all-out at a dealership for the work it can cost upwards of $450. Shop around, do your research, but these are hard to DIY

 

Well I think I might have stumbled across my best option. If I bought the BCM from a local parts store, straight out of the box my car might start and just have a few bugs until taken to a shop for programing, or might not start at all without the additional programing. Then the added cost of towing. I came across a website business that rebuilds, repairs, and sells several types of automotive electronics...aesmodules.com. They offer to fix BCM's at a price and/or will sell a BCM already pre programmed. You have to give them your VIN # and mileage and they will program everything before you install it. Then all you have to do is the few minute remote key-less programming. So far this sounds like my best and most cost effective bet, but I'm looking more into the company just to make sure. I'll post the results after everything is fixed....thanks again for everyone's comments and sugestions.

 

If the BCM was malfunctioning I'd think you would have problems all the time - not just during startup. Your problem sounds like it has more to do with the Passlock system. Some people have reported problems such as yours and solved them by replacing the ignition switch. Just a thought...

 

The Passlock was my first thought when it was just the "security" light coming on some days and staying on and having to turn the ignition to on then pause for a few seconds for all the dash lights to come on then continue to turn over to start. Although the Passlock and Theft Deterrent systems are separate entities, they both tie into the same place (BCM). The faulty Passlock is probably what caused the BCM to bring about my newer issues of lock switches working sometimes, dome light randomly coming on, some dash lights on but radio lights off, the radio security light flashing even after the car has started, etc....I came across a company (Newrockies.com) that guarantees to completely bypass the entire Passlock system with their module. So I figured I would be getting that module as well as a BCM to cover all basis and hopefully all will be fixed......thanks for offering your thoughts.

 

THe car has both a "Service Vehicle" and "Check Engine" lights. They are two different systems. The scan tools you can use will read the Check Engine codes, not the service vehicle (I think only a GM Tech II can read that).
Such as my '02 GT had a Service Vehicle, Trac Off and ABS light. The scan tool I use could read the ABS computer (I had a bad speed sensor). Changed it and first start with the new sensor, all 3 lights were off.

As suggested, the BCM could be the issue.

Also, to my knowledge the BCM needs programming, I'm not sure if you can even start the car with a non-programmed BCM.

This might be a situation better handled by your local new GM car dealer (who would have a GM Tech II scan tool).