Passlock System

I did the yellow wire cut about 2 years ago but car is doing the same thing all over again, however it is now shutting down while driving, the 10 minute reset has to be done on a regular basis, these problems all have occurred during winter weather. I have been through all the tow trucks and mechanics prior to the fix, replacing fuel pumps all the big money items. My suggestion to remedy this problem is quite different... After getting started get full coverage on vehicle and then have someone steal it and then set fire to it..problem fixed! (My suggestion is purely humor intended). We will never buy another GM car again, never had problems with the Fords I owned but the new ones are all probably crap also. I predict that GM will go under even after this restructuring only for the fact that the trail of junk they leave behind points right to them.
Good luck,
Your fellow suckered GM buyer

Tell us how you really feel. People buy price, will always sell.

I want to bypass the passlock 2 system on my 99 intrigue and I've heard you can put any resistor in there and the car will "relearn" the new value. Any ideas on this? Thanks, guys.

Has anyone ever run into problems with a 1998 GMC Extended Cab truck where the vehicle will start then stall, the security light will flash and then immediately go out. I have tried the relearn procedure where you bump the stater and the wait 10 mins...I have repeated this process 3 to 6 times with no results. This problem all started after I replaced the transmission in my truck. I left the key ahead while I replaced the transmission as I had left the truck in neutral in order to roll it back and forth to get it on the car lift. The vehicle ran fine before I changed the transmission as I drove it in the garage with the transmission slipping. Shut the truck off and left the key turned ahead. Removed the trans, rolled the vehicle outside as I was working on it after hours in my uncle's shop. Rolled it back in a couple days later installed the replacement trans. Discovered I had left the key ahead all this time and the battery was dead. Hooked up the battery charger, tried to start the truck and it would start and die and the security light would flash for 5 seconds and then go out. Tried the relearn for 3 times 10 mins and 6 times 10 mins with no change. Anyone have any suggestions? Another interesting thing is the truck will run when I installed a computer for a 97 suburban and it will run, but the computer is unable to be read by a Snap-on Solus scan tool. I don't have a lot of money in the truck and don't want to replace parts randomly...anyone have any knowledge of this system that can point me in the right direction?????:banghead: Thanks for your time!!

This may have been a question addressed in the previous 37 pages. Once I cut the yellow wire and butt splice it, where does the toggle go? Is the toggle on the dash, behind the radio, hanging down below?

Nevermind dorks, I figured it out. I made a video of the step by step procedures.

http://www.youtube.com/watch?v=xnjLkgPpVoY

This may have been discussed previously in the last 37 pages so I'm sorry if this is repetitive. I've had my car towed 5 times, misdiagnosed 4 times and I've had the fuel pump replaced twice, just to find that my security system is faulty. I would have preferred to have the car stolen! I've just been notified by the pontiac dealership that I need a passlock sensor. Does this mean that its too late to perform the bypass discussed earlier?

OK That post talks about just cutting the yellow wire in the passlock system which yes will work until the car's battery fails or goes dead. He'd be better off using my resistor method instead.
Tell about the resistor meathod as I'm new to this forum and can't seem to find it. daylongdriver

I would just write Chevy at the Passlock program.... cac@chevrolet.com

Instead of reading the ohms and installing the proper resisters, how about buying a bypass module off ebay for about 25 bucks.
How well do they work?

Hello from Mexico, here's the solution (worked for me):

Pull out the stereo, then look for the cables coming out from the ignition switch, then start the car, when it's running cut the yellow wire, that will left theft system light on all the time, at this point you will not have problems starting the car anymore, you have been disabled the theft system.

Now, once you have disabled it, you need to do some hack to the bcm to turn off the light, how can you do that ?? Easy, put an ohmeter connected to yellow wire from ignition switch and ground (probably doesn't show any resistance) then put REVERSE (we know that the car wouldn't start) and turn the key to start position, at this time ohmeter shows up the resistor value in the ignition cylinder, then you need to find some resistor value with 10% tolerance up or down to replace (i have to put 3 resistors in serie or continuous to reach the ohms value)when you have it with car started connect the new resistor from ground and now to the yellow wire that goes to the bcm and should turn off the light, if everything went fine you can solder that resistor to the 2 cables and use tape, now you have been disabled theft system and turn off the light too on the dash, because the resistor value always be the same even with the car turned off, and you can start the car rapidly with no problems, it starts and the light goes off, if you have any doubt i left my email: ivanhermida@gmail.com

Regards.

what should I do when i forgot my password on my keys? any help?

A locksmith forgot their password to their keys......ok....:runaround:

I have a 200o Malibu and tried the resistor method the other night. It wasn't acting up at the time. I used a 2.2k 1/4 w resistor installed it as described, it started no problem but the light stayed on. The next morning I started the car and there was no light on, GREAT !!. Now today, 2 days later the car won't start again. The anti-theft light is not on but it acts as if it is. Any one have any suggestions? Should I just try the toggle switch method ?

Thanks for any input

SMOKEY, did you try to check what the resistor value in lock cilinder you have ??? In my case was 860 ohms, so i put a 220-330-330 ohms continuosly on series, that gave to me 880 ohms (10% tolerance) and works great !!!, you need to check the resistor value, not always will be 2.2 k, put a similar resistor value and the light will go off forever, never have the starting problem and the light on again.

I didn't check the resistance. a post earlier said that a 2.2K would be fine.
To update..I had the car towed to an auto electric shop and they told me that they disconnected the bypass that was installed when I had a remote start installed about 10 years ago because it had failed. They recommended a bypass module be installed. The shop said that the car would start now with the key but if I used the remote the car would act as though the anti-theft was engaged. Well I used the remote start and let it run for about 15 minutes then the car shut down as it reached the proper temp. I then used the remote start again again, then went out for a short ride and the car ran fine. Does trhis resistor mod as is work with a remote start or is more work required?

The bypass is used to "trick" the bcm with the resistor, with this resistor "permanent" you will not need a bypass anymore, just your remote starter only, doesn't need to reinstall a new bypass module for your remote starter, just calculate of find the resistor value, put it on between the cables and the light will go off and you can use your remote starter also, i've done this mod a 4 months ago and forgot about the problem.

OK...I just had a look and the shop removed the resistor I put in and put the wiring back to original. So what went wrong with my mod ? It was a 1.5k resistor I used. I cut the yellow wire while the car was running, and soldered the resistor to the half leading to the ignition switch and the other end of the resistor to the stripped black wire. I put a shrink tube on the loose end of the yellow wire. The theft light remained on for a few hours but was out the next day when I drove it. It started for 2 days and then quit. I thought once I cut the yellow wire the anti-theft was disarmed. The only reason for the resistor was to keep the light out. Right ??

That's because you don't check the resistor value before put the new resistor between the cables, also, the resistor needs to be in the yellow cable going to the bcm and the black (gnd) cable, yellow cable for lock cylinder need to be isolated, please check your lock cylinder resistor value and put an equal resistance, that disable your anti-theft system and turn off the light all the time, also you can use your remote starter again, no bypass needed.

Hello. I am here to share my passlock horror story. My car started doing the no start with the security light flashing about 6 months ago. I do the relearn and it works for a while. Then it gets to where I am doing the relearn for every start and finally no start at all. I search the net looking for answers and found that this is a common problem with gm vehicles.

I read about the resistor trick and was ready to try it when I started reading that it is only a temporary fix. Another part of the system like the bcm could fail and then the car would stop starting again. This bummed me out.

Next I started to look for a permanent fix and I found a bypass on this site
How to disable and remove VATS, PASSKey and Passlock Security Systems in GM cars (http://newrockies.com/?ap_id=np9911)

I don't really know much about cars but my friend who installs car stereos put it in for me and it started right up. I couldn't believe it. I don't know if there are better devices out there but I know this one worked for me. I even picked up an 02 Alero that wouldn't start for 800, put the bypass in and it worked on that one too. I gave it to my niece. Anyway just thought I would share a fix I know works. Hopefully this helps.

That's because you don't check the resistor value before put the new resistor between the cables, also, the resistor needs to be in the yellow cable going to the bcm and the black (gnd) cable, yellow cable for lock cylinder need to be isolated, please check your lock cylinder resistor value and put an equal resistance, that disable your anti-theft system and turn off the light all the time, also you can use your remote starter again, no bypass needed.

This works. Did this method on a 95 cutlass. Cost was all of $2 for resistors(had to buy a 4pack, didn't have just one) from radio shack. Over a year ago and not one no start.

Thanks for taking time to speak about this, I arrive to really feel strongly about this and adore obtaining out far more on this issue. If doable, when you get knowledge, would you head updating your weblog with extra details? It's incredibly valuable for me.

Hi 3 days ago I ran into the well known problem of the pass lock system, it took me one day to know my injectors were not pulsing and it was the anti theft, I had my 2004 Classic for about 5 years with no issues until now, while searching I found this thread which lead me find how to re-start my car, thanks to this thread I was able to get it running, I almost read the whole thing but now that the car is running wonder what will be the best solution in the long run, the yellow splice wire, the cut off switch the resistor way or getting a by-pass module, please advice.
By the way I disconnected my battery for one day and I was able to reset the key thing for the 10 min. period.

I recently replaced my ignition switch on a 2003 malibu and i can not seem to get rid of the theft system light. Other sites have said turn car to on wait for theft light to go off then turn car off turn back on and it should start. My problem is that the light will not go off after waiting 10-15 minutes like they say... Any help would be greatly appreciated:confused::confused:

I could really use some help with my car

I could really use some help with my car

Well, first I would like to know why you replaced the switch. Were you having security issues before? If so, you will still have issues anyways.

If you want to try and get this light out, unhook the battery for several hours to completely drain the voltage out of the system. This will cause the BCM to reset which will make it forget it was in "fail/enable" mode of which it is in that now. When you go to start it, it may start for a second then stall and that light will be flashing. If so, leave ignition on for 10 minutes or until that light goes out. Then, shut it off and count to 3 then try to restart. If it still fails to start, repeat above.

If it still fails to start then you must either change out PK2 decoder system or do my bypass method which you will find if you search on here.

Good luck!

I replaced mine because the key wouldn't turn. While waiting for the new part to ship, I spent several hours trying to get it to turn. Since replacement ( about two years ), it has set the fault about three times. 10 minutes with key on usually works. Spec says you need to cycle through that 2 times. found that once works because my daughter tried it.

GOOFY BRIAN - I did one in an Impala; I had to key-on for 10 minutes / for 3 seconds 3 times WITHOUT trying to start it. I think I found that here in automotiveforums

I have 1998 Malibu with a 3100 v6 with 300,000 miles I've had problems with my theft system for years . Finally I installed a toggle switch to the yellow wire behind the ignition while the car was running. It work up until now about 2 years later. The theft light goes off but blinks when I attempt to crank it then cuts off. My car cranks then cuts off. It maybe cranks for a few seconds then cuts off. The theft light blink then cut off. Please help, been trying to get this crank for maybe 3months. My theft system always acts up when it gets cold. I made a post on this at the same time a few years ago before I install the toggle switch.

There is only one problem with this once you install the system with the toggle switch......if for any reason, you disconnect the battery, lose battery power, or someone accidentally flips the switch before starting, you have set the disable code, and now the vehicle won't start.....

The better strategy would be to use the resistor installation instead of the toggle switch.....

The toggle switch method will only work, if you can get the car started again, and then toggle the circuit open, causing the theft light to come on steady again....

So close the toggle switch, and do the 10 minute relearn procedure three times and see if the vehicle starts....if it does, the theft light will go out... with the engine running, now flip the toggle switch to open the circuit, and the theft light will remain on and should restart again when you shut it off....

Ditto what Tech2 says. Who ever came up with the toggle switch idea to bypass these systems should have kept that info to themselves.

With the switch closed, I doubt it at this time the car will sucessfully go through the relearn with 300k miles on the clock. I bet the PK2 system is completely worn out. Only fix would be to replace that or resistor trick. If you do the resistor trick then just do the relearn and you should be OK. Look up my post on here on how to bypass passlock. Go to the last page for instruction.

I wanted to thank tech II for your help on my Malibu. I done what you told me on the relearn process n switch the toggle switch and she started after maybe 2months of sitting. We need more people like yourself around. Thanks again

You're welcome...that's what we are here for.....

Hoping to find a solution. Here is my story. Had many issues with passlock on my 97 grand am. In June of last year my brother did a bypass (something behind the radio I believe). Car has been great until recently. First I came upon an issue removing my key. Car would shut off but not fully back. Found online about the manual release button under the panel under steering wheel. A few weeks later I began having passlock issues again. Once or twice a week I would go to start and none of my instrument cluster lights or gauges would come on and I knew this meant the normal start and stall. But thankfully it would last just a few seconds and everything would pop back on and car would start. This week on Monday I left a store to find that same issue except this time nothing happened after a few seconds. Attempted to do a relearn and still no go. All I managed to do was kill the battery. Left it overnight and went back to it the next morning. After jumping the car and several attempts to start followed by just turning key back and forth it finally came to life. Later that night it started right up. Drove down the road target gas and once again no start. My brother came and again we jumped battery (tried to do relearn while waiting on him). Still nothing. He disconnected battery for 30 seconds and then cleaned the fuse for the instrument cluster and car was ready to go. Worked for about 5-6 starts then again today left me stranded. Bought fuses hoping that was the issue but still nothing. Tried disconnecting battery and nothing. Now we are at a loss. My brother says the bypass should be keeping it from passlocking but clearly that's not working unless there is something else that could be the issue. Can't afford a new car so I need to repair this one. Hoping to avoid the dealership. Any suggestions???

If your security light is NOT flashing, I would guess bad ignition switch.

Not sure what kind of bypass you used, resistor or toggle switch, but in either case, they would have nothing to do with your dash lighting up.....

When you turn the key to on, and the dash doesn't light up, check all your fuses for power......if several have no power, I would be leaning towards the ignition switch....

Did a resister bypass. Replaced the fuses to the instrument cluster last night and the cluster still isn't coming on and car is still starting and dying. I did notice that I didn't start having any passlock issues again until I started having issues with the key not turning back to off unless I used the manual release button on the bottom of steering column. I'm hoping it's just the ignition and hopefully an easy enough fix and I won't have these leaststawhile

Yes it sounds like it would be the ignition switch itself. Now I did work on a '97 Malibu (same system as yours) that was previously bypassed using resistors. Ended up tracing it down to a short inside the instrument cluster. On these sytems, they use a "bulb check" system through resistance that's also tied into the PK2 system. Swapped out the cluster and it's been fine now for over a year.

Ignition switch was replaced at dealer and car was great for a few weeks. Now it is continuing to passlock every couple of days. Usually starts after a 10 min relearn but just waiting for it not to here soon as its done before. Really wish I could fix the problem. I am afraid to go anywhere especially with my kids because I don't want to get stranded.

If it takes a 10 minute relearn to start the car, that resistor bypass was either done wrong, or something is wrong with it...

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I have a 2003 Chevy Cavalier that has not ran in over a year due to anti theft system I believe. Everything seems to work as far as radio, door locks, key fob, etc.. But the car will not start. I used the procedure for the 10 min with key on but the lights on the dash never did go out but still stayed on, antitheft light. When I hook up a scan tool, Actron CP9580A, it tells me no modules present. I tested the grounds circuits at dlc and they where good. Also tested the circuit 1807 for continuity. From the C100 connector to the PCM resistance was 1 ohms so I am going to replace, splice, a section of the wiring from the pcm to the C100 connector. I had also previously replaced the PCM that was freshly programmed. No fuel pressure, engine turns over, compression on all cylinders 175, antitheft light always on solid. If I jump the relay I can get fuel pressure but still no start. Any ideas? I know if I get this thing going I want to disable the passlock for sure.

if it is the passlock problem the car will start for about 2 seconds, then quit and the "Security" light will flash. If this is the case, you need to run through the key-on for 10 minutes routine 3 or 4 times. It was 3 times for my 98 Malibu. I tried that on an 04 Impala and drove myself to boredom before I looked it up and saw that for the Imp it is four times.

dash lights should all be on when key is on but engine is not running - that is how you check the bulbs. On but not flashing.

If you don't get a 2 second start and the security light flashing, we need to look elsewhere. I see that you have done some checks. The no modules present is a good clue and I see that you are chasing grounds and other wires.

Are you getting a spark?


You say that you previously replaced he pcm. Did it run ok when you did that?
Make sure the pcm pins are not bent, not corroded and that the connector is well seated. ( When my Camaro sets random codes, I check the connector and it seems ok for a while. Then things like driving through over a foot of water in Detroit last night makes all kinds of codes come up)

Give us an update when you run the new wires and check for spark, etc

I purchased a programed ecm as I didn't have fuel pressure or spark. The ecm was programmed using the vin number. I still do not have spark or fuel. My wiring to the spark controller is good. All my lights come on the dash good. The Theft light does not flash but stays on whether it is 10 min or 30 min or 1 hour no change. Replacement wire will be here tomorrow I had to order. Kind of a stickler for correct wiring color.

Replace wire to pcm. Still no change as of condition. Here is what I see. Lights that are on after trying to start car. On the right side the Trac off is on, On the left side of the dash the following is on; Check gages, theft system,service,and brake. Note the parking brake is applied.

Using a diagnostic tree for the symptom of no engine module found as my scan tool must find this to proceed to find another module. It told me, a diagnostic tree, to check ground for pin 5 of the DLC. I had put a extra ground into the circuit to ensure ground, but when I checked it again it had a 60 ohm resistance. so I starting tracing the lines down to eliminate how am I getting high resistance. When I remove the light blue connector from the BCM then all the resistance dropped down to .3 ohms. I removed the bcm and inspected the internal circuits and could find nothing out of place as far as heated circuits.

Remember whether it is 10 20 or 30 minutes the lights never change in their appearance in order to relearn passlock. There is no spark and the fuel pump does not run when you first turn the key on either.

Should I remove the ground circuit from the BCM and the DLC and tie them into grounds seperately? That way they do not affect each other? Or is the problem the BCM will need replaced? And if so does it have to be a new one only? $$$$$$

The wiring did not need repaired as there was no resistance in the lines. I replaced the ignition switch with a new passlock sensor. The learn procedure went as it should but when done the theft light came on and stayed on. Still no spark or fuel pressure at any time.. Totally at a loss ..:banghead:

PassLock system has nothing to do with spark or fuel pressure....in some cases it can prevent cranking or not send a fuel enable signal to the PCM which prevents the injectors from firing, but it doesn't stop fuel pressure...

:banghead: I am at loss. My wiring circuits test good. the data lines are good. But the pcm does not turn on the fuel, ignition or the any of the 5volt reference signals. I have all the key and ignition voltages to the pcm and the grounds also to the pcm and the DLC. Why oh why? What can I test.