03 Vue Stalled and Won't Stay Running
 

So, today I went on a coffee run down the street, and while on the way the security light started flashing, and the check engine and service lights came on. This was joined by the engine essentially stalling. Aftera moment, it went away and I was able to get my coffee. On the way back, it did it again repeatedly, ultimately resulting in the engine being shut off immediately after starting it, leaving me stranded and needing a tow. I did a quick bit of research, and it seems to indicate a bad body control module. Can this be confirmed? If it is the BCM, is there a way to rig it up so that I can actually use the vehicle, or will I have to just bite the bullet and replace the BCM?

Have you tried the 10 and 30 min versions of the passlock reset procedure? There are references to it all over the Saturn forums. Try that first. May take three times for it to stick so don't give up right away. Make sure you keep the battery charged fully from another battery or battery charger because the battery will go dead before 30 minutes pass, the reset will fail, and your car battery will be dead.

. It is possible that the issue lies in the part of the ignition that senses the presence of the "correct" key. Not the resistance value. In a passlock II system, the ignition switch has a fancy magnetic detector that is set up so that in theory only the correct key can get in deep enough to push an inner pin type thing near this detector, signalling the correct key is in your ignition.

Things wear over time. Get a new key cut at a GM dealership from the v i n not by copying your existing key. It is possible your key is worn down enough that it is not continuously contacting the piece that needs to be pushed into the magnetic sensing area.

Do you have a lot of keys on your key chain with the Saturn key on it? This can accelerate wear and also cause the key which is worn to not sit square in the lock cylinder, which is also worn, thereby possibly causing a misalignment between the key and the peace that needs to be pushed in to be sensed.

I would try these things in the order listed to see if it is probably something other than the BCM itself.

When that security light starts flashing, the car thinks it's being stolen. In their infinite wisdom, GM built into this system a constant recheck algorithm, meaning while you are driving down the road, and everything is fine, the BCM is constantly querying the ignition and if something comes back wrong or they don't communicate, the car thinks it's being stolen and you get exactly what you experienced. Shutting off right after starting up is, in the absence of other causes, a telltale sign of the fact that security has been tripped.

While I agree that derf is a very intelligent dude, I'd try a couple of other things first. My vo-tech instructor taught me the word KISS. It means Keep It Simple Stupid. And since I'm pretty stupid, I'd try a couple of things first. First thing I'd do is check the connections at the battery and make sure they're clean and tight. Then I'd get the battery load tested. These newer cars are very sensitive to any voltage changes and drops. Hopefully, it'll be that simple. If not one of those two issues, then derf has provided excellent information as to what could be possible causes and ways to check it.

I went back out to it later in the day yesterday, several hours after having it towed home. It behaved perfectly normal. I let sit and idle for about a half hour, moved it around a bit, and it was as if nothing were wrong. Thankfully I have plenty of driveway to work with because I don't trust it to go down the street at present. The battery is good (was just replaced a couple months ago) and the terminals are snug.

I had actually found that relearn procedure yesterday, and was planning to try it when I went back out to the car. But the security light wasn't coming on at all, and it started without any trouble and remained running. I want to repeat the same circumstances as yesterday, see if it happens the same way again, but there's nowhere to ditch it between my house and the coffee shop if it goes funky again except for the shoulder of the road, and I can't leave it there. I expect it would get funky right before I got to the coffee place, and I could chill out in the parking lot for a while, but I'm not enamored with the idea.

These pass lock issues once they start very inconsistent hardly if ever go away unless you replace the active portion of the system. The majority of the time the issue is in fact the BCM. The security system is embedded in the BCM logic. You can get lucky it might be the ignition switch portion. However the majority of the time is the BCM.

Yeah, I thought it might be the BCM, and I see them available for $250 (including core). The notes say programming required, but I'm assuming that's in reference to programming them to recognize the keys with that relearn procedure. Just not sure I want to spend that money on it given how much maintenance seems required for the suspension and brakes right now. I was going to be doing new shocks/springs/struts, end links, bushings, pads/rotors/shoes/drums, and a muffler, and all that is going to be pricey enough without a single expensive electronic component. At least they aren't too difficult to swap out, just have to pull off that center panel of the dash for the most part. I've already done that once to replace the signal relay/hazard switch, and was thinking I'd be doing so again to wire in an FM modulator inline with the antenna and running a headphone jack intot he panel itself.

The programming for the BCM is more involved than just an in-car relearn.

The new/refurbished ones come with NOTHING in the memory. You must have the correct firmware for your model with the options it has loaded with a GM Tech II tool in order for it to function. THEN I think you put it in the car and do the relearn.
If you install it before programming, strange things can happen, as some models store the mileage on the BCM and will refuse to update the dash readout if the dash is not "married" to the BCM. Don't know if this is true for 2nd gen vues. GM will program it by VIN.
An independent shop MAY have a Tech II but they would need to have the most up to date version of firmware for your BCM.

Well, given it's an '03, I'd have to say it's likely 1st gen, so there's that. Given that the vehicle will not travel even five miles before acting up and the nearest GM dealer I know of is maybe 20 miles distant, seems likely I'm better off junking the vehicle. I certainly don't want to pay for a tow that far and dealerships aren't known for reasonable labor or parts costs.

Ok, so I thought maybe I'd let it warm up for a while, see if that made a difference when trying to test it out. Didn't make any difference, but there is now a trouble code. Scanner came up with P0967, and I don't think it's related to this particular issue.

Nope, not BCM related at all. Here's what I found for a Saturn with that code.
https://www.engine-codes.com/p0967_saturn.html