02 LW300: TY for the post! Excellent information.

derf: TY for your advice. Just trying to fix my vehicle. Have you read the components which I have swapped out previously to no avail? 2 Ignitions with matching keys

I would probably go get a key made but the keys which I got with the Vue are both what appear to be plain steel keys. both replacement ignitions are original equipment keys. Going to the dealer and giving them the VIN will not work in my case because the original ignition was long gone before I acquired the vehicle.

For your theory of the key being the problem I have one issue with that. Why does the vehicle have the same issue regardless if I install a known good ignition and key set from a good running Vue? I have 2 other great running Vue's which I have swapped out the ignitions to this one just to make sure your theory is plausible. Ignition and key is not the issue.

The keys for the Vue are the only item on the key ring.

I have noticed that I can get the vehicle to stall "sometimes" if I let it idle and punch the gas pedal a little ways down and immediately remove my foot in park. This quite often triggers the stall and the security light to flash 4 times.

From what I have found those so called "Bypass" systems re just a resistor which you add in line by the ignition to mimic the ignition. Doesn't really bypass the system. I wouldn't want to bypass part of the system in this case. I simply want to bypass the entire system and leave the system there thinking it is functioning normally. Doing so by providing the ECM the signal which the BCM is obviously failing to do from time to time while in operation whenever it feels like it whether that signal be 5 vdc or 12 vdc or a ground. Obviously i can not duplicate a special code as the above posted passlock description states. I have found on other vehicles that "special signals / codes" are really one of the signals I listed previously. That is why I am in search of which wire the BCM sends the injector energize signal to the ECM on.

 

Ok,

Just to be sure -- did you replace the entire ignition lock system? Cylinder + Ign switch itself?

Didn't know the original cylinder was gone before you got it. In theory, you could get that code from a dealer and have one of your extra ign assy's retabbed to match the OEM and get keys cut. Then you could at least carry around 1 key.

So we are down to 2 scenarios if I am thinking correctly.

1) Intermittent connection between the IGN and BCM
2) Intermittent connection between the BCM and PCM.

The nasty part here is you don't know if the BCM is getting bad info from the the IGN every so often, and BCM passing it on to the PCM which will stops enabling the fuel injectors.

OR

If it is an intermittent communication issue between the BCM and PCM.

Based on EVERYTHING you've done, I am going to GUESS that the communications (Serial 2) cable between the BCM is damaged/loose (at the PCM) OR you have a grounding issue near PCM.

Grounding: There are a zillion grounded pins at on the PCM. They are usually grounded via a star pattern (single point grounding) to avoid ground loops. You will need to get a pinout of the connectors for the PCM and figure out IF there is a voltage output for the injector enable function and an associated ground OR if there is only thee serial communications line.

If there is a grounding pin for that injector enable, I'm pretty sure it is either loose a the connector (wiring) or it is a bad connection into the ground splice pack.

As for IGN to BCM --that sounds like it would be just a serial data line.

You can repair the the serial communication lines, but I don't think you can just remove them from the circuit. Without the password being sent from the BCM to PCM, the PCM will not enable the injectors. Unless you can come up with a way to fake out the PCM.

This is why this implementation of Passlock just sucks.

Stalling after flooring it in park is prob the rev limiter kicking in which kills the fuel injectors.

 

I just found this: No idea if it is true

https://repairpal.com/gm-passlock-security-light-issues

Operating states of the warning light on Passlock systems should be:

On for bulb check
Off when engine is running
On steady if a fault occurs
Flashing in the learn mode

If that is true, your system is somehow kicking back into learn mode. Maybe it is letting you drive in a failsafe mode until some predetermined amount of time, then kicks into relearn mode because the Passlock security password is not correct or is getting garbled.

1) Try timing the FIRST amount of time until stalling. I know you said it is random, but that may seem as such to you based on for example stalling at different places along the same route.

I'm reaching at straws here -- it's worth a try --then we will know if it is reverting to learn mode in a systematic way after first start.

If this is the case (and I'm not saying it is) then there is another underlying issue that is causing the relearn to not "stick" or the PCM and BCM are losing communication (Serial data as discussed in earlier posts.

2) Maybe try a 10 min or 30 min relearn even though the password supposedly has been learned

3) I also saw a post by someone who said they had to leave the key in the on position for an hour to clear out all the passlock info, THEN fight with the relearn procedure until it finally worked.

4) Another poster indicated that the body ground from the neg batt term lead was poor. Once he disconnected and cleaned it, he reassembled, did a passlock relearn, and all was well.....that and clean the neg terminal and cable end on the neg battery lead.

5) Do you have a battery charger? It is possible your relearn is not sticking due to the battery being run down during the procedure.

6) There is a post regarding Chev trucks w passlock II (what you have -- no saturn ever had Passlock I). It claims to work, and people suggest putting in a toggle switch for the times when you will need a cut wire to be briefly reconnected.

See PERMANENTLY Disable and Remove GM Security Systems They claim to bypass the entire system by patching into the BCM. I think they are replacing the BCM's Fuel enable command to the PCM with a permanent fuel enable message regardless of the behavior of the theft deterrent module in the BCM.

Interestingly, they claim to bypass the entire system, but you still have to do a passlock relearn after installation for the car to run. I suspect they are intercepting the signal from the key cylinder and never letting the BCM process it .

The passlock relearn is probably required b c it is necessary for there to be any output to the PCM from the BCM, and there's just no way around that.

Sems pretty comprehensive if they are ensuring the fuel enable message is always received.

I would call them in your case, b c the system seems to be back in learn mode while driving and we don't know why

 

Thanks for the information.

I'll go down through your subjects one at a time.

1. Yes, I replaced the entire ignition lock and key assembly twice.
2. As for grounding I have removed the PCM from the engine, cleaned the contact area, ground cable, engine ground cables, body ground cable as well as the contact area on the hardware and re-installed to ensure a good ground at all locations. In addition I used jumper cables to connect the negative post o the body and the engine block for added insurance.
3. As for the pins in the wiring harness going into the PCM I do not have a schematic of these plugs showing which wires should have what readings. Either way, to ensure that I did not have a pin connection issue I removed a known good wiring harness from a good running 3.0 / automatic Vue and installed it into this Vue with no change.

Note: The only wiring harness which I have not changed is the under dash to under hood fuse / relay box wiring harness. Surely not looking forward to changing that one, if required.

4. Serial Data Line?? Where is this located? Between the ignition and the BCM?
5. You mentioned that a rev limiter could cause the stall when tapping the pedal off of idle. That couldn't be the issue due to the fact that the stall happens some of the time before the engine ever hits 2000 RPM's. Even when it revs and does not stall it has a hesitation at first then takes off. Fuel pressure is great, before you ask.
6. Timing the stall: The stalling is completely at random. Sometimes it can be started and left idling and stall on its own in 15 seconds or 5 minutes or revved up and down and stall from 5 seconds to 2 minutes or driven for 10 seconds to a minute. Totally random and without warning.

Note: Yesterday I went out to move the vehicle ack into the shop for the night and when I went to start it it would not start and the security light was flashing. not the first time it has done this. When it does this the only fix I have found is to leave the ignition in the run position for like 5 minutes then turn the key off and turn back on. When it is turned back on the security light stays on normally for a second or two then goes out and the vehicle starts normally.

I will go through the steps you mentioned in the second reply post and let you know what I find out. I am also going to look at the wiring harness between the ignition and the BCM to see if it can be replaced individually.

The module which those folks sell does exactly what I am trying to do. The only thing i am lacking it knowing which wire the signal is sent on from the BCM to the PCM (ECM). If I knew that I could just take care of it. Shocked that I can't find a ECM and BCM wiring schematic (wiring diagram) and information to figure this out.

Thanks

 

The schematics are in the factory service manual. I purchased the complete set for my 2002 L series on Ebay for about $80.00 if I recall correctly.

 

Jumper cable wire from eng blk to frame? Was it 4 or 2 gauge?

KIDDING. You are definitely someone I want to build indestructible furniture for me after we get this solved.

As for the rev limiter thing, I thought you said when you floored it and let go it would stall. THAT'S why I mentioned rev limiter. If it happens at 2000 rpm then def not rev limiter and I need to be more awake when reading posts.

That type of stalling stems from another issue I believe...to maybe be discussed later.
-------------------------

Serial Data lines/communications:

I'll try not to make this more complicated than it isn't.



I know GM used and may still use (Class 2) Serial data networks -- I'm pretty sure they did back in the day (2003).
--------------------
Excerpts from
Diagnosing General Motors Communications Network Problems - Auto Service World


The following summarizes Class 2 Serial Data:

The network uses a zero to Seven Volt signal; the voltage rests at Zero volts when there is NO communication; the transmitted data is a variable pulse width signal; Class 2 is found at Pin # 2 of the DLC (Diagnostic Line Connector) , and is a single-wire network system; and GM uses what is referred to as a “splice-pack” to connect modules and the DLC to each other for network communication.

The Class 2 bus circuit number and the wire color for this system, each vary, according to the individual module(s). To diagnose this network system, you will require the following: A lab scope and scanner; a high-impedance DVOM; a component locator; a vehicle-specific wiring diagram, which is very important to have; and most importantly, a healthy dose of patience.

-------------------

So, like you said, WHICH WIRE IS IT?
Don't know how far you read into the info at the newrockies site, but they have the installation instructions for their unit for your vehicle, complete with wire color codes, etc -- so you may get some good out of that.

I would think the only connection between the BCM and PCM would be a communications one --- same thing with the ignition. but DON'T quote me o that. They are just raising a V on a communications wire from 0V to something above 2.2V (per old digital logic, I'm guessing from memory).

It's like the communications wiring from

1)the IGN to the network backbone to the BCM or
2)BCM to the backbone to the PCM

4 segments of wire

is purposely being driven >0. Ths makes sense when the BCM commands a Passlock check while you are driving as it is programmed to do so. For the BCM NOT to receive an injector enable command back from the PCM during a PASSLOCK check means either
From BCM to PCM
1)the signal was sent and never received
2)the signal was sent and not interpreted correctly
3)the signal was sent and not interpreted b c it was unintelligible
4)the signal was never sent

FROM PCM to BCM
4)the signal was received and not acted on
5)the signal was received and not acted on b c it was unintelligible
6)the signal was never received from the BCM

They say this is a single wire communications system, but there HAS to be a GROUND as REFERENCE.
--------------------------
I will postulate that there is a loose or damaged communications ground that is vibrating, When it intermittently lifts from ground, this is interpreted as a positive (NON ZERO) Von the communications line itself(since ground is now >0 V ). The V potential is SMALLER than the BCM expects to see from the IGN, so it orders a PASSLOCK recheck, which of course fails and shuts down the vehicle.

A wiring manual (maybe in a haynes / chilton's, at least the pinouts for the PCM and BCM connectors) seems kinda mandatory if there is any chance of slaying this demon.

Did you ever check the CKP (Crank Position Sensor)? I can't remember and am too lazy to scroll back.

 

Thanks for hanging in there with this issue Derf.

I partially removed and disassembled the under dash wiring harness (from another 2003, 3.0, automatic Vue) and traced which wires run where for the security system since I have been unable to locate a wiring diagram. The only wires which I see that run into the engine compartment are two beige wires which are twisted together and an orange wire with a black stripe. I fully intend to monitor the voltage on these wires once I get back to working on it. This is following all wires which are not running between the ignition and the BCM then out of the BCM and into the engine compartment. I have not traced them further than where they enter the engine compartment as of yet.

By the looks of the information on that link you posted seeing the voltage is sent by "pulse width" I will not be able to duplicate it.

Yes, I changed the crank position sensor and the camshaft position sensor as well as verify the tension and condition of the timing belt and the correct timing. Just to ensure that there wasn't an issue with the sensors reading some sort of misalignment between the crank and cams.

I wonder if there is any correlation between the number of flashes and a certain type of fault? GM always did this in the years past.

Haynes manual has wiring diagrams but they conveniently leave out all aspects of the security system. Not sure on Chilton's.

I fully agree with you with what is happening to the signal. I've been doing this stuff for decades and this one really has me scratching my noggin!

Have not had a chance to get back on the vehicle yet. Working on the house. Plus, frustration requires a break from time to time!

 

Let me add one more oddity to the list of things this Vue has been doing. I probably should have mentioned this in the beginning and it might shed some light on the underlying issue.

When the ignition is left on in the run position the throttle body seems to cycle from time to time. Humming, clicking and chattering. Then the air intake hose is removed from the throttle body I can see that when the clicking happens the throttle plate opens and closes slightly repetitively for a second or two. The hum almost sounds like the fuel pressure sounds when the fuel pressure is building but that is not the cause of the sound. Fuel pressure is correct and constant at all times.

Finally, I have gotten to the point where the engine will not start at all, regardless of what ECM, BCM, Ignition/key set combination I try to use and teach. All it does when I turn the key on is the security light comes on, blinks 4 times, goes steady for a while (a 30 seconds to a minute) then blinks 4 times again repeating this over and over again. I am going to get a complete matching ECM, BCM and ignition/key set from another known good 03 V6 automatic Vue and swap everything out just to ensure I am not missing something here shortly if I don't find something else soon.

 

Some things are apparently not as straightforward as it seems, if this post is correct
--------------------------
Engine stalls but restarts / P1629 code - SaturnFans.com Forums


I just had a 2003 Saturn Vue 3.0L in my garage with that code and the same drivability complaint. I scanned all controller's and found P1629 in the ECM. I have a Saturn shop manual. It is a signal that the passlock sensor sends out. Code P1629 is THEFT DETERRANT FUEL ENABE SIGNAL NOT RECIVED. First you need to check the BCM 15 amp and BCM/ECM/CRUISE/ ABS 10 amp fuses in UHJB. clear ECM and BCM DTC'S.
Security System (Pass lock Relearn Procedure) You will need to go to the dealer for that procedure. To see if that is causing your problem. If it doesn't fix the issue your having well its a very large circuit. The signal starts at the pass lock sensor and is sent to the (BCM) Body Control Module to the (EBTCM) Electronic Brake/Traction Control Module it you have that option. Then the signal is sent to the (TCM) Transmission Control Module. Then to the (ECM) Engine Control Module. That is a password that is continuously from the BCM to the ECM. OK
What you need to do is if you have some one with a scanner take a ride with you. That person needs to go into each controller till the vehicle stalls out and loses comunication with a controller. Assuming you don't have any electrical problems the vehicle I had in my garage had a bad ECM. It was taken to the dealer and they programmed a new computer and the problem has not returned.

 

Post happy today. Maybe something useful will come from it.

Generic P1629 definition

-----------------

DTC P1629

Circuit Description

The powertrain control module (PCM) controls the fuel injector operation based on a vehicle theft deterrent (VTD) password from the vehicle body control module (BCM). When the ignition is first turned ON, the BCM sends a programmed theft deterrent password to the PCM. The PCM acknowledges the password and responds to the BCM that normal fuel injector operation will continue. When starting the engine, the PCM looks for a password from the BCM through the Class 2 serial data circuit. If the password is not recognized or not present, the PCM will disable the engine. If an incorrect or no password is received, fuel enable will not occur and the engine will not start. The Security indicator will flash on the instrument panel cluster (IPC) for approximately 4 seconds. If an incorrect or no password is received more than three times, this indicates that the engine is disabled for at least 10 minutes and that the Security indicator will illuminate solid on the IPC for approximately 3 seconds then flash on the IPC for 10 minutes. If the PCM loses communication with the BCM within the same ignition cycle, the vehicle will be enter fail-enable mode and continue to run on the following ignition cycles.

But, if previous post is true, the path is not direct.

Wait, that previous post was probably describing the Serial 2 data lines! He thought they were all connected in series........

You REALLY need a wiring diagram set to get to the bottom of this.

Oh, check the wiring carefully at the CKP plug and trace it back to the PCM -- if the crank posit sensor stops sending pulses intermittently due to wiring issues......
Doubtful but worth a looksie

The fact that it coded before you replaced it is what brought up the issue in my mind. You haven't driven it since, correct? It WOULD stop it from starting on its own by killing spark and fuel. Check if you have spark to see if the CKP circuit is intact.