Passlock System

[UnhappyImpalaOwner]

Originally Posted by AF_Dali

...I started my car first, then cut the yellow wire, measure the reistance value using a multimeter, find a same value resistor and connect it as instructed. The anti-theft light is gone, and no start-up problem since then....

A few questions in trying to get the steps down exactly.
(1) The original procedure by ponchonutty mentioned cutting the yellow wire before starting the car. But AF_Dali stated he cut the wire after starting the car. If the wire is cut with the car running, won't the security light come up and will it turn off after the correct resistor is installed? Do you install the resistor with the car running or leave the car running just long enough to get the resistance value.
(2) I've read elsewhere of putting in any resistor value and having the car relearn. Any risk in doing that and the car not relearning or is the main problem the time it takes to relearn.
(3) Stupid question - I assume when measuring and soldering to the black wire, you are doing so after pealing back the cover off the wire somewhere in the middle of the wire. I know you don't cut it.

[AF_Dali]

Originally Posted by UnhappyImpalaOwner

A few questions in trying to get the steps down exactly.
(1) The original procedure by ponchonutty mentioned cutting the yellow wire before starting the car. But AF_Dali stated he cut the wire after starting the car. If the wire is cut with the car running, won't the security light come up and will it turn off after the correct resistor is installed? Do you install the resistor with the car running or leave the car running just long enough to get the resistance value.
(2) I've read elsewhere of putting in any resistor value and having the car relearn. Any risk in doing that and the car not relearning or is the main problem the time it takes to relearn.
(3) Stupid question - I assume when measuring and soldering to the black wire, you are doing so after pealing back the cover off the wire somewhere in the middle of the wire. I know you don't cut it.

Hello,

Here are the answers to your questions:

(1) As far as I remember ponchonutty's step is to reset the system if necessary so that your anti-theft system won't obstcle your from starting your car. After the car is started, you cut the yellow wire while the car is running. Nothing will happen except the Anti-Theft light is turned on. You can now turn off the ignition and try to start the car again. You will find the start up problem brought by the Anti-Theft System is gone, but the anti-theft light is on.

(2) I am not sure about the mentioned relearning risk. ponchonutty's method works smoothly on my Malibu just as what he had described.

(3) Yes, you don't cut the black wire, you peal the insulation off in the middle of somewhere convenient for your measurement and later on soldering. Of course, you don't need to start the car while pealing the yellow and the black wire, or while soldering the resistor.

Good Luck on your repair! If possible, post it back to let ponchonutty know how his method is working.

[UnhappyImpalaOwner]

Thanks AF_Dali,

If I understand correctly here is the plan
(1) Start car
(2) Cut yellow wire (security light comes on)
(3) turn car off
(4) strip yellow wire ends and part of black wire.
(5) start car (security light is still on)
(6) meter between yellow (going to ignition switch) and black for resistance
(7) turn car off
(8) solder correct resistor between yellow (going into dash) and black
(9) start car (security light is off)
(10) post results to AF

Just want to get the steps correct so that I don't create a 4 door paperweight.

[AF_Dali]

Originally Posted by UnhappyImpalaOwner

Thanks AF_Dali,

If I understand correctly here is the plan
(1) Start car
(2) Cut yellow wire (security light comes on)
(3) turn car off
(4) strip yellow wire ends and part of black wire.
(5) start car (security light is still on)
(6) meter between yellow (going to ignition switch) and black for resistance
(7) turn car off
(8) solder correct resistor between yellow (going into dash) and black
(9) start car (security light is off)
(10) post results to AF

Just want to get the steps correct so that I don't create a 4 door paperweight.

Yes these are the steps that I took to have the problem fixed.

[N.J.C.]

Whew! Finally read through all 25 pages! LOL! That takes awhile!

My problem started last Fri night, the 24th, on my '98 S10 ZR2. I spent a few min. trying to start the truck, and like most, it would start, run for 2 sec. and shut down. I automatically knew it was something electrical. But, I've never studied anything about the factory secuity systems on GM vehicles. Never needed to...didn't have anything new enough to have these problems until I bought this truck about a month ago. My old '96 Sonoma didn't have passlock or passkey....somehow.

I spent the better part of 5 hrs doing research on the 'net that night. I'm a researcher, that's what I do. Not to mention, I'm an administrator on a forum board that is just like this and a moderator on two others (ATV sites). I help people with problems on their quads all the time. Been working on those boards for several years.

After spending the better part of my weekend learning more than I ever cared to about these GM security systems, I've finally gained a huge understanding of how the entire system works. I've been a mechanic back in my day and even work w/ electrical stuff for my job (local IBEW).

That being said, I've tried a little of everything and had some good luck and some not so good luck. I did get the truck to run the next morning after leaving the battery completely disconnected for about 8 hrs while I was sleeping. It started and ran just fine but the light stayed on. I've went through the relearn proceedures (which worked) and even pulled a diode that I found that's supposed to disarm the entire system when pulled. Didn't do squat. So if you read anywhere to pull a black diode labeled, DRL, don't bother. It won't hurt anything, but it won't disarm the security system either. Everything has been fine since the relearn proceedure but I haven't cleared the codes on the BCM so the light is just stuck on. Kinda light fixing an engine problem fixed, but not clearing the DTC's (diagnostic trouble codes). The light will just stay stuck on until the codes are cleared. Not a problem for me....I don't stare at my idiot lights when I'm driving and paying attention to the road! Unlike some of you....LOL!

I'm happy to say the truck is currently running...and has no issues starting except for the light is stuck on. I haven't done squat to it short of the relearn process...that's it. I was fully aware of the bypass module and what it does after getting a quote on a remote starter just after recently buying the truck. For those who don't understand what the aftermarket bypass module does (which has to be installed w/ an aftermarket remote starter), it simply does the same thing as installing resistors inline between the infamous YELLOW and BLACK wire. A bypass is required to circumvent for remote start applications. If left unchecked, it will lock down the fuel injector rail, and you will then need to tow it in to GM for evaluation, and resetting. This Passlock Bypass Module is designed to momentarilly allow the engine to remote start by sending a proper coded pulse to open the fuel rail passlock injector cut off circuit. The output from an alarm/remote starter would then shut down the pulse, once it has detected the engine has engaged, and preserve the integrity of the passlock system. The only difference from individual resistors and the bypass module, is the bypass module learns the resistance values and automatically matches it. It's a simple automatic process that eliminates testing for the resistance values and buying and installing those matched resistors. With the module installed, it will always match the resistance, no matter what it is. So, for those of you who aren't comfortable testing resistance, searching for the right resistors and installing them, you can search for an aftermarket bypass module used for remote starters and simply have it installed. Any car audio shop that installs remote starters will do it. You don't have to have the remote starter installed if you don't want to, but it you have the extra money, then do while they are in there. Remote starters are nice, but not needed if you just want the bypass module installed. That's just one fix...or idea to throw out there.

OK, on to my MAIN question. Most of know (if you've read all 25 pages and paid attention) how the system works and what components are in charge of controling it all. We also know the end result of a faulty code is the fuel injectors getting shut off to prevent auto theft. Sooooo, how many of you have thought about working your way backwards and go directly to the component keeping the car from running? I'm talking about the fuel injectors. I myself haven't looked into it yet, but I will. Is there possibly a way to take the fuel injectors offline from the security system? Is it possible to allow them to fire and opperate correctly without getting shut down by the BCM and/or PCM? If I'm shooting for the moon and it's never possible, then disreguard this last paragraph. I'm just thinking out of the box from what I've been reading over and over for the past three days.

In the mean time, my '98 ZR2 will be getting the remote starter and bypass module. That's what was going to happen before all this started in the first place. I made my decision to install a remote starter the day I bought it almost a month ago. I installed one on my '96 4x4 Sonoma years ago and won't go without one on this truck.

Good luck to all. Respond as you see fit. I'll be checking this thread for more problems and reading and helping as I can. Sincerlely, one hellava patient guy!

[ponchonutty]

NJC, welcome aboard! As you have already read, I seem to be a land shark on this subject. I didn't mean to but mearly just fell into it. What you asked about backward bypassing the system would be great if you could find a way. The biggest problem would be that to do it I'd bet just about any amount of money you'd need to reflash the BCM somehow to get it to ignore the Passlock system. Also, if you could do it, my guess is that GM dealers would let that be an option outside of warranty.

For the time being, my method seems to be the best way to go. BTW, you will get a major bill from your remote starter installer. If that light is on when you go to get it installed, they'll have a real good time with your truck unless they are aware what I say on here. The reason is the exact thing you stated...."these bypasses read the resistance everytime you start the vehicle". Well, if the resistance is off like enough to get your security light to come on the bypass is worthless.

On the '98 s-10 series the BCM is down below the center part of the dash behind the black cover. The plugs face the gas pedal. Over time someone could get that a little wet from slush and snow causing the leads to corrode. I'd take the cover off and unhook the plugs and check for problems there. Then reconnect them and see what happens.

Since you now have that light on, that means the BCM is in "fail enable mode" You can read about this in your owner's manual. It means that you need to get it fixed fast. The system is so bad now that the BCM is ignoring it but it'll only do that for so long.

[N.J.C.]

Originally Posted by ponchonutty

NJC, welcome aboard! As you have already read, I seem to be a land shark on this subject. I didn't mean to but mearly just fell into it. What you asked about backward bypassing the system would be great if you could find a way. The biggest problem would be that to do it I'd bet just about any amount of money you'd need to reflash the BCM somehow to get it to ignore the Passlock system. Also, if you could do it, my guess is that GM dealers would let that be an option outside of warranty.

For the time being, my method seems to be the best way to go. BTW, you will get a major bill from your remote starter installer. If that light is on when you go to get it installed, they'll have a real good time with your truck unless they are aware what I say on here. The reason is the exact thing you stated...."these bypasses read the resistance everytime you start the vehicle". Well, if the resistance is off like enough to get your security light to come on the bypass is worthless.

On the '98 s-10 series the BCM is down below the center part of the dash behind the black cover. The plugs face the gas pedal. Over time someone could get that a little wet from slush and snow causing the leads to corrode. I'd take the cover off and unhook the plugs and check for problems there. Then reconnect them and see what happens.

Since you now have that light on, that means the BCM is in "fail enable mode" You can read about this in your owner's manual. It means that you need to get it fixed fast. The system is so bad now that the BCM is ignoring it but it'll only do that for so long.

Good news. Cleaned ignition key switch (lock cylinder) out and removed all extras from the ignition key. It's been working well....no security light at all now. No security problems period. Didn't have to do any altering of any kind. All is safe to install a remote starter and bypass. No fail enable mode from the BCM.

Poncho, I like how you dubbed yourself the "land shark". Are you trying to say no one else has the capability of learning and understanding a complex system as well as you have? Cause believe me, it doesn't take me long to learn anything electrical or mechanical. Just because I haven't had the need to deal w/ a faulty GM security system doesn't mean I won't learn the aspects of it fast...trust me.

As for a remote start. If...and I mean IF I were to allow an installer to touch my truck it would be out of pure convienence....the convienence of not touching a single tool and letting a personal friend/installer do the work. I don't mind supporting a friend and his local business. I'm more than capable of installing anything electrical as well as any mechanical work. Lets just say of the 8 or so GM cars/trucks I've owned, none of them have made a trip to a mechanic let alone a dealership. I have already spoken to my installer and informed him that I won't be needing an overpriced bypass because I will be installing my own bypass in the form of resistors. He's excited to hear the news. One less issue out of the way...less time to spend IF he does the work. As I stated before, I've installed remote starters before. Not a hard job. Only an inconvienence when it's cold outside.

You seem to have the need to give yourself a certain title as if to say "I'm the king of this castle". Whether you realize it or not, that's the vibe you presented. I'm no "newbie" to public boards/forums and see this phenomenom quite often. If your are confident in your knowledge and are truely here to just help, then there is no need to title yourself. With that said, thanks for the responses to the questions on this board. And thanks to those who ask the right questions. I'll post my data and/or results as they happen for those in need of answers.

[ponchonutty]

whoops, sorry. Didn't mean to come off like that. What I meant by "land shark" is that I look for posts containing issues with GM's security then give my advise.

Yes, some people have reported decent findings with the cleaning of the ignition cyl. and the removal of unneccessary keys and junk off of the key ring. Most of the vehicles that I've bypassed though the people had tried this with mixed results and just don't want to take the chance of being stranded. Infact, I just bypassed a '99 Malibu this morning!

[N.J.C.]

Originally Posted by ponchonutty

Yes, some people have reported decent findings with the cleaning of the ignition cyl. and the removal of unneccessary keys and junk off of the key ring. Most of the vehicles that I've bypassed though the people had tried this with mixed results and just don't want to take the chance of being stranded. Infact, I just bypassed a '99 Malibu this morning!

Have had good results still. I have one of those little quick disconnects on the ignition key so when I hop in the truck I remove it from the rest of the key ring so there's no extra weight hanging from the ignition switch.

The bypass is still getting done once I install the remote starter. It's starting to get fairly cold in the mornings so that's coming very soon.

To those who have this happen to them and are frustrated and don't know what else to do, try diconnecting the battery completely. I tried it once for a half an hr and it didn't work so I just disconnected it over night and reconnected it the next morning and the truck started right up. That was the end of my problems until I changed what I mentioned above. Thankfully I was already at home and didn't have anywhere important to go. How long the battery needs to be disconnected is a mystery to me. It probably varies but mine was disconnected for at least 8 hrs but I wasn't in a hurry the next morning.

[ponchonutty]

Disconnecting the battery to reset the BCM is at most a 10 minute thing. I am sure it was just a coinsidence that the over night trick worked. Also, if the PK2 is on it's last leg and the car has been driven around with the security light on, it's normally not a good idea to disconnect the battery. Doing so can completely lock you out from being able to start the vehicle.

[jerlinux]

I have installed a remote start in a 2003 Malibu. In order to make this work, I had to purchase a 791 bypass module to get around the Passlock. As near as I can tell, this module starts and runs as long as the remote start allows the 791 to find a ground.

I wonder if a 791 could be wired into my 2002 impala with a manual switch that would ground the 791. Then, if I once again saw the security light, I could flip the switch, ground the 791 and start the car. Once the car was running, I could unground the 791 by flipping the switch.

I do not think that a remote start would be required and the wiring would be pretty simple.

Has anybody tried this?

[03Alero]

I appreciate all the info that people have put on here. I have an 03 Olds Alero, and I"ve been dealing with this problem for quite some time. It got worse and worse, until I was finally having to reset my system 2-3 times per week. I stumbled upon this forum, and I decided to follow the resistor route that many have suggested. I followed the following steps:

1) Started car and cut yellow wire (Security light came on)
2) Measured resistance. I'm not sure if it was me or the multimeter, but I was having a hard time getting a good reading. My best estimate was ~1500 ohms.
3) I installed a 1500 ohm resistor between the yellow wire and the black wire and put everything back together.
4) I started the car, and my security light is still on. I guess it is in bypass mode, and the resistor I installed wasn't close enough to the value it was looking for.

So, my question is how do I force the BCM to reset when it is already in bypass mode? I followed the normal procedure that I used to follow when the car wouldn't start (put key in "On" position and wait 10 mins), but that didn't do anything. Any suggestions?

Thanks!

[ponchonutty]

Originally Posted by 03Alero

I appreciate all the info that people have put on here. I have an 03 Olds Alero, and I"ve been dealing with this problem for quite some time. It got worse and worse, until I was finally having to reset my system 2-3 times per week. I stumbled upon this forum, and I decided to follow the resistor route that many have suggested. I followed the following steps:

1) Started car and cut yellow wire (Security light came on)
2) Measured resistance. I'm not sure if it was me or the multimeter, but I was having a hard time getting a good reading. My best estimate was ~1500 ohms.
3) I installed a 1500 ohm resistor between the yellow wire and the black wire and put everything back together.
4) I started the car, and my security light is still on. I guess it is in bypass mode, and the resistor I installed wasn't close enough to the value it was looking for.

So, my question is how do I force the BCM to reset when it is already in bypass mode? I followed the normal procedure that I used to follow when the car wouldn't start (put key in "On" position and wait 10 mins), but that didn't do anything. Any suggestions?

Thanks!

OK you sure you got it back together correctly? The resistor should be between the black wire and the cut yellow wire going to the BCM and not the dash and DO NOT CONNECT THE 2 YELLOW WIRE ENDS BACK TOGETHER. Also, when reading the resistance don't forget to meter the other end of the cut yellow wire after you have it started. If all of that is correct then you have another problem going on. You may need to run another wire from chassis ground to the black ground wire as well. If or when you are 100% you've got it right you can play your dice and unhook the battery for 5 minutes then try to start it. It'll either work or lock you out and then you'll have to do the PK2 relearn sequence.

[ponchonutty]

Originally Posted by jerlinux

I have installed a remote start in a 2003 Malibu. In order to make this work, I had to purchase a 791 bypass module to get around the Passlock. As near as I can tell, this module starts and runs as long as the remote start allows the 791 to find a ground.

I wonder if a 791 could be wired into my 2002 impala with a manual switch that would ground the 791. Then, if I once again saw the security light, I could flip the switch, ground the 791 and start the car. Once the car was running, I could unground the 791 by flipping the switch.

I do not think that a remote start would be required and the wiring would be pretty simple.

Has anybody tried this?

Yes, in theory you could get it to work but then again you'd be paying 1000% more for that bypass instead of just getting resistors.

[ponchonutty]

QUESTIONS ON PEOPLE WITH PK1 vehicles such as a '97 Cavalier. I curious of any of you that have the PK1 version and had problems AND did this bypass. Did it work? The reason I am asking is that the PK1 system has a "bulb check" setup. I had messed with one a long time ago but it didn't work plus I think the vehicle had other issues as well. I'm trying to figure out how to bypass a PK1 which I suppose a simple relay wired off of the ignition switch could work.