+

+

=

 

I take it you never got around to fixing yours?

 

nope cant figure it out. Im waiting to find someone who can do a tune for me but now its not starting at all. I did the 10 minute 30 second cycle so long last time I drained a fully charged battery. I dont know wtf to do now. I cant toake it to the dealership cause Im broke as fuck but it sucks having my truck sitting for so long.

 

Wow. I think there is a point where the passlock module just craps out and will not send the correct signal no matter what you do.

Did you replace the passlock module? or just trying to do a relearn so it will get you by?

 

just trying to do a relearn. I was trying to get it started so I could cut the wire and just drive like that till i can get a tune but Im SOL on that front now too

 

Yeah, sounds like you just need to replace the passlock module itself now.

 

Im gonna try the tune first. thats probably the cheapest thing I can change out

 

How much is the tune? You can get a passlock module for about $65 bucks and then do the re-learn yourself.

 

Where? a tune is about $100. Ill try that first if its cheaper. Tune is about $100 but itll do a little more then jsut fix the passlock problem

 

RockAuto Parts Catalog


Then you follow the instructions on how to replace it in my original post. Then do a re-learn.

 

how much would the dealership charge to reprogram, do you have any idea? the new switch is $43

 

Thats the thing. The dealership will just do the re-learn which you can do yourself.

 

ahh ok so the relearn is doing the 11 min off 30 sec on cycle? The article you posted says it needs to be hooked up to a GM computer.

 

As an alternative to hooking it up to the GM tech II computer programmer you can do the 11 min 30 sec cycle thing.............I believe.


Can someone else chime in on this?

 

How does geting a tune fix it?

 

you can have the whole VATS system turned off

 

Like with hp tuners an that will fix my problem?

 

From what I've read yes. But I've also read where it sometimes comes back.

 

I don't feel like retyping everything, but look for the thread where I am discussing this with Unicknn.... it explains why all of these things are not foolproof.

 

yeah, I read that thread before.


This thread is intended for those of us who want to actually replace the passlock module and repair this the correct way.

 

If you want to replace and repair it the proper way...get ready to shell out major money. If your lucky it's just the interlock ignition that is bad. If it's not then you have to replace the rest of the module which is like 700$. It's not cheap to "repair" passlock. Passlock is not just a single component. It's a multi component system.

 

As seen here its only about ~$65 to do yourself if you can do the relearn on your own. The part you can get through Rock Auto or even ebay.

Pass Lock How To: Ignition - Chevy Colorado & GMC Canyon

 

Again....that is just the ignition module portion of passlock....there is additional component to it... that generates the signal which passes to the other portion which then generates the real signal which is passed to the BCM/PCM. Hence the comment of if your lucky its the ignition module.

 

Right on, got you now. So from what I understand is that you have 3 components

1. The key cylinder

2. The passlock module which the key cylinder slides into ( this is more likely the culprit )

3. The BCM / PCM.

 

Nope... It's more like a 4 part system:

1. Key Cylinder
2. Ignition Passlock Module (This sends the resistance signal. Hence the reason for needing to do a relearn)
3. Passlock module which recieves the Ignition resistance signal, verifys it's good, and then sends the digital signal to the PCM/BCM to enable fuel injectors
4. PCM/BCM

Now that having been said...I have no clue where on our trucks that #3 piece is. It may be integrated into the BCM on the new CAN bus vehicles. On the older Gm vehicles it was buried under the dash. Normally a 2x2 inch box. Thats the expensive piece, because it is taking raw electrical signals and converting it to a digital data stream. That's the other problem with Passlock.....GM is not consistent on things. Results may vary. That's why I hate PASSLOCK! :ugh:

 

Interesting. From my research I have read that the black piece in the above picture is what sends the resistance signal to the BCM indicating that the passlock is correct, then the BCM sends a signal to the PCM allowing the engine to start up.

The other other passlock module that you suggest exists is in the BCM itself. Which i doubt in about 90% of the cases with trucks that exhibit this type of problem is bad.

The black piece above rotates and is prone to wearing out.


Here is a good read i found on how the system works.

The Passlock(TM) system is provided in order to prevent vehicle theft if the ignition lock cylinder is forced to rotate. The Passlock(TM) controller reads the coded Passlock(TM) data signal. The data consists of a voltage generated by a voltage divider network created between the Passlock(TM) assembly and the Passlock(TM) controller. If the data is correct , indicating rotation of the lock cylinder with the proper mechanically cut key, then the Passlock(TM) controller sends a password to the powertrain controller via serial data to indicate that fuel should be delivered to the engine. The Passlock(TM) controller also interfaces with the driver displays subsystem to indicate, via a security telltale, the Passlock(TM) subsystem status and acute subsystem failures.

The components of the Passlock(TM) system are as follows:



The ignition switch

The body control module (BCM)

The security indicator on the instrument cluster

The engine control module (ECM)


BODY CONTROL MODULE (BCM)
The body control module (BCM) contains the logic of the theft deterrent system. The BCM provides the 5-volt reference to operate the Passlock(TM) sensor. The BCM also measures the voltage of the off/run/crank voltage. The voltage measured will indicate whether the Passlock(TM) sensor has been activated and whether the resistance value from the sensor is a valid value or the tamper value. If voltage measured is in the valid range, the BCM compares this voltage to a previously learned voltage code. If the voltage codes match, the BCM sends a serial data message containing a password to the engine control module (ECM). If the voltage codes do not match, or the voltage is in the tamper range, or there is a circuit fault, the BCM will not send the correct password to the ECM, and the vehicle will not start.

ENGINE CONTROL MODULE
The engine control module (ECM) contains the remainder of the logic of the theft deterrent system. If a serial data message containing a valid password is received from the body control module (BCM), the ECM will continue to allow the fuel injectors to operate. The ECM will allow the fuel injectors to operate until it decides there is no valid password coming from the BCM. If the ECM does not receive a serial data message, or receives a serial data message with an incorrect password, the engine will crank and will not run or will start and stall immediately.



FUEL LOCKOUT CYCLE
When it receives a password which is incorrect or a password which indicates tamper and the engine control module (ECM) disables the fuel injectors, the fuel injectors remain disabled for 10 minutes even if the ignition switch is turned from the RUN position to the OFF position.

CHANGING THE PASSLOCK(TM) COMPONENTS
The following components contain codes or passwords, or must learn codes or passwords for the Passlock(TM) system to allow the vehicle to start:



The ignition switch

The body control module (BCM)


If any of these parts are replaced, a learn procedure must be performed. Refer to Programming Theft Deterrent System Components. If parts are replaced and a learn procedure is not performed, the engine will crank and will not run or will start and stall immediately.



As I said, the key itself doesn't "learn" or "know" anything but there are other components in the PASSLOCK system that do contain "logic", and if the ECM can't get a good reading from the key cylinder *housing* (not the key or the key cylinder), or the BCM, then we'll have this problem.

I can't say what it might cost to diagnose and correct the problem. A good locksmith might be able to handle this.

 

Yeah...I know how the system works. As far as wearing out...the big issue is not that it wears out, but rather the system is unable to compensate for the increased contact oxidation over time, as well as the increased resistance that happens over time. I agree that a vast majority of the time it's prolly not the second piece of the system that goes bad, its the interlock ignition piece. However especially in unicknn case, it may be more than that as repeated relearns have had no effect. That usually means there is something going on. Or it is just so toast that the resistance being generated is completely out of wack. In your case it may just be the interlock. It never hurts to try the cheap method first.

 

Cool, we agree then. Would you happen to know if you replace the interlock if you have to get it reprogrammed at the dealership or if you can do the re-learn yourself?

 

From my experience and understanding it has to be done at a dealer unless you some how get lucky and get an interlock that exactly matches what your current expected resistance is. The reprogramming tells the other piece what resistance it should be looking for.

 

I see. So the 30 minute relearn procedure wont work then. I wonder if there is a way you can choose which interlock module you need. I know you can measure the resistance on one of the wires.

There is a auto shop right up the street from my house that is pretty high tech. Im going to go talk to the manager and see if they have a techII machine.

 

I just talked with my mechanic buddy and he said that as long as you get the same resistance module the 30min relearn will work. If not...Tech II time. It's also possible for the relearn process to not always work on the first try. Eitherway we are discussing. I may be blending passkey and passlock together. He also just let me know there is actually like 4 different systems....but not 100% either way. I found this article...might help some...
http://www.the12volt.com/installbay/uploads/FEF_N555L_7-02B.pdf

So in conclusion....I have no freaking clue. I would follow what the guy in the cfan thread said, and be prepared to need a Tech II.

 

The mechanical portion to replace the module itself it fairly simple. Just need some hand tools and possibly a steering wheel puller. It can be done in a couple of hours max. Possibly even just do it in the parking lot of the dealership then push the truck to the service area.

I know you can measure your resistance and find out what you need but I have not found a source yet that tells you if there are different part #'s for the different resistive values of the passlock module. if you can narrow that down it would almost be a plug ans play deal.

Can you ask your buddy if there is a way to order a specific value passlock module?

 

my buddy has a tech II so that should save me a little bit of money.

 

I was just about to send you a PM. I've been researching your issue nick, and I honestly think ignition is the first place to start with you. If you have a buddy with a Tech II have him scan your truck and he should be able to diagnose your issue real fast. From what I've read on HPtuners and getting more of an idea of how VATS ties into everything....I don't think that just turning it off will help you. VATS will keep the system running, but if the BCM is not even recieving a good signal from the switch, it doesn't matter because it won't relay the signal. Turning VATS off just allows you trick the truck into running, such as using a remote start which bypasses the system.

 

so you think I ought to start with the part atxjax posted a link to?

 

Yup. With VATS off, it just allows you to hot-wire a vehicle like in the old days. You still need to have something to start the ignition process.

 

Dealership or Shop. As long as they have a Tech II you are fine. Sorry for the confusion.

 

well got the part on order. Ill start there and hope that works. Got a show on the 3rd so hope it comes in by then so I can make it out

 

Awesome. hate to say this but looks like your the guinea pig for my project. Hopefully it will work out for you. definately update this thread once you get it done. And since you dont know what resistive value interlock your getting try doing the re-learn on your own first, if it doesnt work then go to a dealership.


Put a charger on your battery.

 

Hope to hell that works nick. Definitely let us know how it goes.