03 V6 Vue stalls while driving + security light flashes 4 times Help please!
 

I have a 2003 Saturn Vue which stalls. It will stall at any speed or just sitting idling. When driving it stalls and the security light flashes 4 times then if the vehicle has enough speed still it will take off on it's own again, otherwise it has to be restarted which it does easily. When idling it will stall and the same 4 flashes happen. The gages do not loose power or anything else in the vehicle. There are no trouble codes in the computer.

Since I have an identical Vue for parts I have the convenience of being able to swap out known good parts for troubleshooting. The following are the parts which I have swapped out with no change to the problem:

Body control module x 3
ECM x 2
crank position sensor
camshaft position sensor
ignition and key assembly
engine wiring harness

Does anyone have experience with this problem and have a known suggestion for a fix? I have researched the problem on forums and see that this seems to be a problem with Saturns. The thing that really throws me for a loop is the security light flashing 4 times just like it flashes 4 times as you begin the reprogramming procedure when you replace an ECM or BCM.

Any help or suggestions would be greatly appreciated

Thank you, Andy

Additional Information:
 

I have also replaced the Air Mass sensor, both coil packs, map sensor on the intake, the fuse / relay panel inside the middle console and the large orange relay under that panel as well which has made no difference.

Going to change out the engine compartment use / relay box today in hopes that the problem is inside of that component.

UPDATE: Engine compartment fuse/ relay box exchange made no difference. Computer only has one code which is P0700 loss of communication with transmission control unit. The transmission operates excellent!

With the vehicle OFF, When you turn the key from OFF to RUN (not CRANK), how many times does the security light blink during the self test period?

You need to scan for codes again with a more advanced scanner that an read B (body) codes, U codes, etc.

I will almost guarantee you that the advanced scanner will pull B codes related to the malfunction of the BCM

The BCM controls this light as well as the entire security system--and MANY other things......

As far as I know the security light should never be blinking driving down the road.

Do you have any other strange seemingly totally unrelated issues with the vehicle?

The ONLY situation I can think of right now would be if the Vue is a 5 speed manual, , the BCM thinks the security system has been tripped and is sending messages to the PCM to intermittently kill spark or fuel. It then is resetting back to "no security issues" status, and since the clutch is still engaged, you're doing the equivalent of popping the clutch to restart it while rolling down the road.

The security system relies on the ignition switch, the BCM, and the PCM.
They all have to be synched up and talking properly to each other or the security system (part of the BCM) will be a mess.

Is the key loose in the ignition? If the end of the key does not stay in contact with the innermost tab inside the ignition SWITCH (not cylinder), then the car may think it is being stolen. All three pieces of the system need to be present and communicating. Take the Vue key off your keyring and use just that in the ignition w nothing hanging off of it.

If you are lucky that is the issue.
But more likely your BCM is toast.

If you get another one, the BCM needs to be reprogrammed to your VIN AND the BCM needs to go through a LEARN cycle in order to re-synch with the PCM. All this with the key in the ignition AND can only be done at a GM dealer as far as I know.

Reply and update
 

As for the answers to your questions:
1. The security light comes on one time and stays on maybe 2 seconds then goes out when the key is turned from off to run. There are no other issues with the vehicle. Everything else works properly.

2. I used my more advanced scanner which has "Saturn enhanced" capabilities. At first, from all the previous changing of parts and messing with everything there were 24 enhanced codes stored. All "P" codes except for one "U" code. I recorded those codes and erased them and nothing re-posted in the memory while running. I started and ran the Vue till it stalled. When it stalled it set a P1629 (Theft Deterrent fuel enable signal not received) and a P2419 (Evap Emissions system switching valve circuit low) codes.

*** Does anyone have any idea from what would cause these codes to happen?

The vehicle runs excellent up until the engine stalls regardless of engine RPM, temperature or any other parameter. The vehicle has the automatic transmission.

3. The key fits snug in the ignition. After all I have tried 2 known good ignitions for this troubleshooting procedure.

4. As for the BCM being toast, I have installed three and none of them made any difference in the problem. I went through the learning cycle with each as required when you change either an ECM, BCM or an ignition switch assembly. All of which I have changed. The BCM is not VIN specific, as I have found through changing several of these components, as dealers would have owners believe.

Does anyone know where I an find a wiring schematic / wiring diagram for the body control module and Powertrain control module (ECM)? The manual I have shows some of the wiring but does not show security wiring or the signal wiring from the BCM to the ECM which powers the injector system (security shutdown). If I find out which wire that is coming from the BCM then I can fix the problem by completely bypassing the security system issue.

Sounds like you found the stalling problem.

GUESS:
As long as the theft deterrent check comes out fine when the car is started,
(ign cylinder, BCM and PCM all agree on the passcode), all is fine. The BCM must be sending a "Theft Deterrent fuel enable signal" to the PCM or vice versa.
It seems stupid to me to design a constant theft check into the system while the vehicle is running. I doubt that, given the sporadic nature of its occurrence.

I think it is more likely to presume that the security system, which is part of the BCM, is triggering the anti theft procedure while the car is running, and there MAY BE a communication issue between the ign sw and BCM or BCM and PCM. It may actually be that the communication can not occur while the vehicle is running, so the BCM can't send the spurious theft check Passcode to the PCM or doesn't receive a signal back, so it kills the fuel.
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The simplest explanation still lies with the ignition. A quick opening of the security contacts would likely trigger a theft deterrent check sequence. You have already checked two known good ignition cylinders.

But how worn is your key?

If it is worn down at the tip or jiggles around in the cylinder, it may be just worn enough to not be keeping the contacts for the security system closed.

Go to a Chevy dealer and get a new key cut from the VIN, NOT your current worn key.

The chances of the communication going wonky with three different BCMs seem unlikely.

+1 Derf, I always get new keys cut by code obtained from the dealer. My local dealers even still have Saturn blanks in stock!

Problem not solved! Keys all look good and not worn down or loose. Remember, this vehicle does the same thing regardless of which ignition switch / key is installed in the vehicle. I have installed 2 known good ignition switch assemblies with coded keys from excellent running Vue's for troubleshooting this problem.

Need to know what wire coming from the BCM supplies the ECM the fuel signal so that I can bypass the security system entirely.

If your Vue uses the same system as the L series it does not look promising.
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Please. Your key is 14 yrs old. You have no idea how worn it is until you compare it to a freshly.cut key. Please spend the $9.00 to buy one.

Also, have you added anything magnetic to your key ring lately?

As for the system design, they apparently DID put in a constant theft check while the vehicle is running.

If you are hell bent on murdering the security system there are 598764 posts on other Saturn sites + zillions of people selling devices that supposedly bypass the system.

$10 for a key.is a drop in the bucket.
Let go of the pride thing and go for it.