I have saved a 2003 saturn vue from becoming a firefighter training session, i got it for next to nothing. after a few visits in which the bcm was replaced 2times, the following things were done by me.

BCM was replaced by shop 2x
I changed the ignition twice, as the key was able to be removed. and relearned the new keys
i changed the Crank Positioning Sensor
i changed the throttle body

there's a few things im unsure about, the security light blinking because the car shut down? or because that caused the shut down?

service engine light and check engine light come on also during shutdown, i have no codes,

Vehicle doesn't stall, but completely shuts off.

CAR DOES RUN AND DRIVE AND START RIGHT UP, WILL IDLE ALL DAY. GOING DOWN THE HIGHWAY I CAN GET THE CAR TO RESTART IF I KEEP GIVING IT GAS, IN TOWN AT SLOWER SPEEDS THE VECHILE HAS TO BE PULLED OVER AND RESTARTED. THEN IT WILL DRIVE AGAIN UNTIL IT DECIDES TO SHUTDOWN. It is interminant and not related to one action. sometimes i can drive it 3 towns away and it will be fine, other times i get a block away from home and it shuts down.

i have been driving like this for a month now, kinda scary but i know how to manage it. Just had a baby boy and can not put him in this car, just been a go to work car.

i know this post is all over the place, lack of sleep, a rough running car, a newborn ,and work all have my brain fried. maybe one of yall can help save me.

 

To the best of my knowledge, the BCM constantly checks the passlock sensor in the ignition switch. Not just when you start the car.

The upshot is that if the BCM cannot communicate with that ignition switch sensor or it can communicate but does not receive the correct answer, it will tell the ECM that the car is being stolen as it has a rogue key or whatever else in the ignition instead of the correct key. The ECM then kills power to the injectors and the engine stalls dead.

If you have truly relearned the new ignition cylinder and key and they have been synced with the BCM properly AND the BCM has been married to the ECM, it would seem like all would be well and this should never happen. And the security light should not be flashing while you are driving.

My guess is that either the ignition switch is not the correct one for your particular vehicle or the pass lock sensor in the ignition switch itself is damaged.

Having to replace the ignition twice makes me think you were only replacing the ignition cylinder. The passlock ignition sensor is part of the ignition switch not the cylinder.

If the Passlock ignition switch sensor is loose or damaged, it will likely intermittently not detect the key, which would **** off the BCM which would tell the ECM to kill the injectors and the engine is no longer running.

Perchance did someone try to steal this vehicle and pop the ignition?

Get the vehicle scanned for codes using a true code scanner that reads the p codes as well as b codes, U codes, etc.

There are likely some b codes or body codes that should shed some light on this.

But my best educated guess is the ignition switch which should be entirely replaced. Use a new cylinder so everything is fresh and aligned.

I'm confused as to why you would need 2 bcms and two ignitions in the process of trying to repair the vehicle.

For the record, Saturn S series cars did not have bcms until 99 so that was not an issue for my vehicle mentioned in the other thread.

 

I guess I should have worded it alittle better, but the shop changed the BCM twice because they were pretty sure that was the problem, also the security light does not flash when the car is running and driving only after it shuts down this is security light flash three times and then the light turns off, along with multiple other lights check engine service engine etc I'm assuming this is because of the shutdown but I am unsure, I changed the ignition twice because the first one I got at the junkyard the key was able to be removed while driving so I assume that was part of my issue I went to the junkyard and pulled another ignition the whole assembly changed and wired that, and then the vehicle would not start the security light was flashing all the time until I relearn the new keys,. So so basically to sum it up the shop change the BCM twice because they thought that was the issue, I changed the whole ignition switch because I thought that was the issue, the security light only flashes when the vehicle shuts down. I hope this helps a little bit and yes I will need to get a scanner myself I scanned it with a basic OBD2 that I purchased on Amazon but I don't get any codes.

 

Oh look, you have company

The snippet below is taken from a Saturnfans.com post:

03 VUE stalling/security light flashesMy vue is having the same issue that I've read about on this forum. It's a 03 with the 3.0. It's stalling while driving, the dash lights up like when the key is first turned on and the security light flashes 3 times then it catches all the lights go out and it will continue to drive. Or if driving slow you have to stop and it will immediately restart. It's produced no codes, and it's not the crank position sensor. I've read about this exact problem on here but never a resilousion. 03 VUE stalling/security light flashesMy vue is having the same issue that I've read about on this forum. It's a 03 with the 3.0. It's stalling while driving, the dash lights up like when the key is first turned on and the security light flashes 3 times then it catches all the lights go out and it will continue to drive. Or if driving slow you have to stop and it will immediately restart. It's produced no codes, and it's not the crank position sensor. I've read about this exact problem on here but never a resolution.

---

The answers posted in the thread are all over the place which is why I did not copy them or link them..

When you originally start the car, how many times does the security light blink?

The fact that you are able to sync the new keys through the ignition switch and have the BCM recognize that and successfully talk to the ECM to have the vehicle run at all tells me all three components are capable of operating correctly.

But that does not mean all the time.

The constant checking of the key cylinder pass lock sensor is going on in the background and actually, the security light should not be flashing while you are driving because if the engine is running, the result of those checks are that everything is okay as far as passlock is concerned.

Is the shop using bcms pulled from junk yards?
Are they the correct part number for your year and model Vue? A refurbished BCM programmed to match your VIN should not need to be replaced.
If you are using junkyard bcms as is, you have no idea if you are pulling bad or good bcms.

Thousands of Saturns with bcms that failed went to the junkyard precisely for that reason. So you don't know what you're getting..

Is this a manual or automatic?

Ultimately, I believe the issue is with passlock/security. The shop most definitely has a scanner that can read body codes. If there are no stored body codes, you are no closer to fixing the issue.

I still believe it is a communications issue or functionality issue in the ignition switch, though I will now add the BCM as a possible culprit if it is not a refurbished BCM programmed to your VIN.

Sometimes you can get away with one that is close enough provided it has full functionality. But that's a crap shoot you can only diagnose by having it not go bad.

Also, if the key itself is worn as I would expect from a junkyard ignition key, it may not be continuously detected by the passlock sensor in the ignition switch. If you have a lot of keys on your key ring and this is the issue, then you are jiggling your key around the entire time you are driving.

Without watching the communications data between the ignition switch and the BCM, you will not ever know which is the culprit unless you replace them on at a time.

So why was this vehicle dirt cheap?
Did you ever discuss any potential issues with the owner before purchasing? Not that they necessarily would have admitted to this. Just doesn't matter either way to me, just trying to build the history.

There is also a long shot chance that the communication issue is between the BCM and ECM which would have the same effect during the passlock sequence, shutting down the injectors when the handoff from the BCM to ECM does not occur properly. I've seen one post where someone claimed ECM replacement fixed the issue. Again, you'd have to be monitoring the communications between the BCM and ECM on a constant basis in order to catch it misbehaving if it is.

If it is affordable and makes sense to you to do it, I suppose you can scavenge for an ECM in a junkyard although a refurbished ECM programmed to your VIN would be the proper way to go.

Short of taking it to a GM dealer, preferably Chevy, I'm not sure this can be figured out in any way other than trial and error. I'd also be surprised if an independent shop had the equipment and the firmware files access to reprogram refurbished BCM and ECM if you obtained them.

For the record, I have only given bad advice seven times in 19 years and they were all questions about the Ion.

Yeah, right.

I've explained as best I can how passlock works, why your car is probably stalling and restarting, and where to look for the problem. The junkyard ignition is most worrisome but like I said there are other possibilities especially using a junkyard BCM and slim chance that the BCM and ECM are not communicating properly all the time.

So I don't have much else to say on the matter that I haven't said already. I don't mean that to sound rude, but I believe I've given you all the information that I can.

Feel free to show all of this to the guys at your shop. It was rare back in the day to find mechanics experienced with working on Saturns. Most of those folks have retired, so the knowledge lives on only on the forums and only with people who bother to stay on the forums 20 years later. It's not that an independent shop can't figure it out, it's that it will take much more time and money to do so.

If you don't want to put money into a 16 old vehicle that may have other issues we haven't even discussed, now is the time to stop.

Food for thought.

Please stop back and let us know how it went and what you did. There are just about no posted solutions for this issue and you'll be doing the Saturn community a great service.

Peace

 

Forgot to ask. What does the odometer read as the mileage and what is the real mileage on the vehicle?

 

So just to answer your questions, I too believe it's the passlock system, and I appreciate that answer,. I got it dirt cheap, the gentleman I bought it from his dad had a heart attack and passed away this was one of the vehicles that was left in the garage, after he paid the local shop close to $2000 in labor with no answers, they replaced the BCM twice with what looks like junkyard bcms, that's also correct.this work was done before I got the Saturn because it kept shutting off. And now I ended up with it for $500 because I seen potential in fixing it. Your right I don't know what I was thinking if the shop couldn't fix it how could I?, might be a better training session for my fire company.

 

I appreciate all your time thank you for all you do!

 

Milage is 80k, this is why I wanted it for $500 the thing is in mint condition inside and out.
I'm not sure if that's actual or not...... The BCM work was done by the shop prior too and the reason for me getting the vehicle

 

This guys father really took care of this Vue, right down to all maintenance work sheets, inspection receipts and oil change logs. The Vue is beautiful. Such a shame