Engine stalls but restarts / P1629 code

[kristina813]

Hello-
Hoping I am not the first to experience this problem, so want to know if anyone is aware of a resolution they may have experience with??
I own a 2003 Vue/V6 Automatic and am experiencing the engine stalling/dying while driving. I first brought into the dealership in February and they said there were some misfires but no codes-so no fix at that time.

It has been intermittent for MONTHS, 9 out of 10 times will completely die and I am able to immediately just pull over, put into park and restart. This ONLY occurs while I am driving, I can be in a parking lot at low speeds or just on the freeway-I do see the security light on, but also the other dummy lights flash wildly, then engine dies. Brought it into the dealership wednesday and they pulled a P1629 code and stated the BCM needed replacing(security fuel cut off-found pcm signal from bcm not valid or present cutting off fuel).
Ok so I drive it home and on my way to work the next day it does the SAME EXACT THING. Am bringing back to dealer and just wondering if it really may be something with ignition lock housing sensors, or maybe even fuel pump... Thinking they better have kept my old bcm and give it back or eat the $$$ on this one since it did not solve the problem... HA!
THoughts??
Thanks!!

[fdryer]

DTC P1629 Theft Deterrent System - Cranking Signal

Its difficult to interpret this code as it can have two different meanings, to me anyway. I'm inclined to think that the crank position sensor (CPS) has failed intermittently and kills the engine. Whether it affects the theft deterrent system is not altogether understood in relation to the BCM. The anti-theft system is part of the BCM programming but the cps signals are used by the ECM to operate the electronic fuel injection system. The ignition switch contains part of the anti-theft system.

Normally, when the ignition switch is turned the anti-theft system detects the key position and simultaneous code that's sent to the BCM for decoding; a valid decode will be used by the BCM to enable the ECM to operate otherwise it will disable one or two crucial signals necessary to operate the fuel injection system; the fuel pump signal and injector pulses. When all's well, the cranking engine to allow a start-up requires the cps timing signals fed to the ECM to allow it to run the fuel pump, initiate the ignition/spark electronics, and pulse the injectors. As long as the engine rotates the cps continues to output timing signals to allow the ECM to run the engine. The cps is the electronic heart of the EFI system. An intermittent cps signal is akin to a heart attack; uneven heart beats or irregular cps signals won't allow the ECM to run the engine and the engine randomly dies.

The security light being on and the other flashing lights points to the BCM working erratically. There may be two separate issues or the original BCM is still in your Vue and not a replacement. You'll have to ask the service manager why the problem hasn't been repaired when they state otherwise with replacing the BCM. This is just my opinion.

[kristina813]

Wow-thanks for the quick response! Yeah that makes sense...
I drove the thing the whole weekend without the two repeat symptoms it gave me friday, and brought it back to the dealer today. They called me to tell me they tightened the junction box bolts(that they found them too loose I am interpreting)..Makes me wonder, since it sounds like the cheaper and simpler thing to do, even in the event they did pull a P1629 code-why didn't they check that first, or AT ALL before giving it back to me with a $300 computer part charge?? Hope to get that answer tomorrow! Maybe I'll just bring up one of them TSB's I don't think has been addressed on my vehicle and see if they can do anything for me...lol
Now I'm wondering if I even needed that new BCM at all...but guess it shouldn't hurt going ahead a replacing it before something(other) in it goes...I'll just try to think of the justification as prophylactically I guess... :dizzy: