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Pontiac Grand Am Security Passlock Problems



  • did u turn the key all the way back past the off position after reseting the passlock
  • Go to
    There are some tips at the bottom of that article on troubleshooting your system. It sounds like you might have a short or an open in one of the wires between the passlock module and the BCM. Good luck.
    Dick B
  • My 2004 Alero which uses the same parts had an issue with the ignition switch. You could actually pull out the key with the engine running. The switch was replaced a few months ago and no problems since. Could be a pass lock problem along with a BCM under the glove box.
  • I don't think I would have gone to the expense of replacing the ignition switch just because I could pull the key out of the ignition. Many cars in the 50's and 60's were manufactured that way. Even so, this would have nothing to do with passlock, since this is a mechanical function, not electrical.
  • In the 2004 alero it has the pass lock 2 witch does not have the sensor on the key. It instead has the sensor in the ignition switch assembly and when the tumblers or something else inside the switch get really loose or worn the sensor does not send the correct resistance to the bcm which in turn shuts down the fuel injectors.
  • Actually, what you say is true of all of the following cars:
    1999 - 2004 Oldsmobile Alero
    1997 - 2003 Chevrolet Malibu
    1999 - 2004 Pontiac Grand Am

    They all are equipped with Passlock II systems, and do not require a key with an embedded resistor. In these models, the resistor is embedded in a module that is molded into the side of the tumbler mechanism, This resistor is activated into the passlock circuit when any key is used to turn the locking mechanism. When the resistor is activated, a voltage between 1.5 and 9 volts will be present on the yellow wire [circuit #1836]. If the voltage is not what is expected by the BCM, then the bcm will begin flashing the "Security" light, and will not send the correct code to the Powertrain Control Mocule. In turn, the Powertrain Control Module will deactivate the fuel injectors, causing the engine to shut down.
    If the voltage on the yellow wire is within the allowable range, the vehicle can then be left in the ON position, and the BCM will, after 10 minutes, remember the new voltage, and will shut off the "Security" light. If you then turn the ignition off for 5 seconds, and then try to re-start the vehicle, the Security light will remain off, and the car will start.
    If for some reason, the voltage on the yellow wire is not within the tolerable range, the "Security" light will then stay illuminated solid [not blinking]. If the relearn procedure does not work, the solid "Security" light indicates that the yellow wire is either broken, or shorted to something else in the wiring harness.

    That's about all there is to the circuit.
    1. "Security" light off - Everything working correctly
    2. "Security" light blinking - Wrong voltage. needs relearn procecure
    3. "Security" light ON - Short or open in the wiring
    4. "Security" light ON but car starts - Faulty wiring, and Passlock system is in bypass mode. Bypass mode will remain until battery is disconnected or discharged, at which time Passlock system will cause the injectors to be de-activated.

    Dick Berger
    Instrumentation Engineering (retired)
    General Motors Proving Ground
    Milford, Michigan
  • re: to dick berger light is blinking when door is open , put key in ignition start car no light at all, driving and car shuts off. reset passlock runs battery dead even without the lights on,half charged the battery and the alternator charged it the rest of the way full could a battery set off the passlock system if it drops below 12 volts
  • lovemygrandamlovemygrandam Posts: 330
    edited February 2013
    It is common for the battery to drop below 11 volts when the starter motor is engaged, as when starting the car. The battery normally recovers to around 12.8 volts within seconds after the ignition switch is released from the "start" position, and returns to the "Run" position. During charging, the alternator generally puts out over 14 volts. Normally, the battery can go well below 10 volts without effecting the operation of any of the vehicle electronics.
    Unless you have a VERY bad battery, I suspect there is something wrong with your wiring... possibly a bad ground point, or a short. The fact that your "SECURITY" light is blinking when the door is open indicates faulty wiring, since there should be no connection between the "door ajar" switch and the "SECURITY" warning light, which is completely controlled by the BCM. Also, the Passlock system will not shut the engine off when driving, as this is a safety concern. [shutting down the engine will stop your power steering from operating, rendering the car hard to control.]
    During the learning period, the only things that draw current from the battery are:
    The PCM and BCM
    The dash lights
    The Daytime Running Lights
    The radio, if it is turned on
    The AC/heater fan, if turned on
    The Brake lights, if you have your foot on the brake, or your brake switch is out of adjustment.

    A reasonably charged battery should be able to hold a charge under these circumstances for at least 45 minutes, so if it is running down during the relearn, either the battery is on it's last leg, or there is a short somewhere in the wiring that is causing excess drain on the battery.

    Place a voltmeter on your battery, turn your ignition to the run position, and make sure all accessories and fans are shut off. If the voltage is above 11.8 volts and doesn't drop below that after 10 minutes, your battery is likely ok, but I suspect yours will drop slowly and get down to 10 volts or less.

    Your next task should be to measure the current drain from the battery when the ignition is on and the engine not running, the AC fan and the radio are off, light switches are off, and the dome light is off. You can find out how much current should be drawn from the battery in the shop manual for your vehicle.
    Dick B
  • tks il give that a try
  • mr. berger or anyone i need a used rear end for a 1999 ford expidition part # S 935 C-1 739757D02 373 RAITO 975 RING SIZE
  • How much are you willing to pay and where are you?
  • i know it sounds crazy but i found carrying an extra fully charged battery and switching them out starts my car ive been trying to find the problem with mine for 4 months now wish i could help more
  • not sure ive never bought one before and changed it out the used parts yards around here and my friends tell me it should cost about 150.00 or so what do u think im not trying to insult u at all with that figure i just dont know i live in ludington michigan and i havent had a car to drive for 2 yrs and i really miss being able to go to work without getting a ride or shopping for food i dont have alot of money and il probly have put this in my self i guess if the tag numbers match up youl have to let me know wat its worth thks so much for getting back to me and your time helping me figure this out blessings to you
  • Hi all,

    Hopefully some one can help me. I have a 2002 Grand AM and was plagued with the passlock issue. I found a website with a supposed fix. ( seemed like a good idea at the time. I got my car started by resetting the computer and one fix was cutting a yellow wire below your dashboard and that should solve the issue but leave your security light on. I didn't mind the security light on as I just wanted my car to run. It worked for a day and a half and now my key will not even turn in the ignition and I cannot even move the gearshift into neutral to get my car off the street. I tried resetting the computer again and reconnecting the wire and then resetting the computer. Nothing is working any advice?
  • Your ignition switch is linked to your steering wheel, and your gearshift by mechanical linkage. Something is binding one of those linkages, keeping you from turning the key in the ignition. This is a mechanical issue, not electrical, and has nothing to do with the Passlock system.

    There is a possibility that you may get your key to turn by jiggling the gearshift lever a little while turning the key. This may be the reason for the binding. Also, try jiggling the steering wheel while trying to turn the key, as this mechanism sometimes binds until you relieve the pressure on the wheel in one direction or the other.

    By the way, how were you able to reset the Passlock system without turning the ignition switch.

    Also, doesn't the instructions at instruct you to also add a resistor to the circuit after cutting the yellow and black wires?
  • Thanks for responding.

    If it is mechanical it happened at a really odd time. I tried both to no avail.

    Prior to my cutting the wire my car was fine except the for the passlock issue. My father in law got it running by either removing the battery cable for 10 minutes or by leaving the car in the "on" position for 10 minutes, not sure which.

    After i cut the wire the car was running fine. Two days later the key wouldn't turn. Since then I tried taking the battery cable off. splicing the wire back together and nothing is working.

    As for, there were three fixes listed on his site.

    1) cut the yellow wire while the car is running, this will leave your dash security light on( my choice as i didn't care about the dash light as long as my car was running)

    2) cut the wire and splice in a switch so you can toggle it on and off at will.

    3) the fix with the resistors.

    I figured i could cut the wire to get me going now and at a later date add the resistors. I can't do that now because i cannot recalibrate the system as it requires me to put the car in the "on" position.

    Lucky enough where we just got a new car so i don't need it, but its stuck in front of my house and i can't even get it into neutral to roll it into my driveway so i can get it off my insurance. I would love to be able to get more than a tax write off or selling it to a junk dealer for cheap when the engine is still in great shape as is most of the rest of the car.
  • With this additional information, I'm sure that something non-electrical is preventing your key from turning. The possibilities are:
    * The Gearshift link cable may be causing the key to not turn (Automatic Transmissions)
    * The Steering locking mechanism may be causing the key to not turn (manual transmissions)
    * Something is broken inside the lock mechanism.
    * The wrong key is being used, or the key has become worn and no longer aligns the lock tumblers correctly to allow unlocking the vehicle.
    * The actual ignition switch, [which is attached to the back of the key mechanism] is binding, broken, or has come out of proper alignment. This could be a possibility if, you unplugged the ignition switch connector while gaining access to the yellow wire and it's bundle.

    Before going to the dealer, why not remove your radio, unscrew the two bolts that hold the ignition switch in the dashboard, and pull the switch out through the radio cavity and try to get it to turn with nothing attached to it, then you will know whether or not you need a new ignition switch. You should be able to find one at a junk yard for far less than the $400 or so that the dealer will charge to put in a new one. Then, also do the resistor mod, and you won't have to worry about passlock problems ever again. See the alternate instructions at Passlock Fix, No Soldering

    Also, there is another reason for installing the resistor, instead of just cutting the yellow wire. After you get the vehicle started, and the yellow wire is cut, you cannot lose power to the Body Control Module. If you do, as in.... disconnecting the battery..... the BCM will reset out of the passlock fail mode, and again try to protect the vehicle from theft. Since the yellow wire is now disconnected, you will not be able to perform a relearn, so you won't be able to get the vehicle started without re-connecting the yellow wire, performing the relearn, starting the car, and then cutting the yellow wire again. That's the reason for installing the switch.

    When I wrote up the instructions at, I figured it was considerably cheaper to install a resistor [4 for a dollar] rather than a switch [$4.50].

    Dick Berger
    Instrumentation Engineering, GM Proving Ground
  • I am so frustrated with this passlock issue. I have had several issues and have even had the computer reset and was told by mechanic not to use any key but the main one. This worked for awhile and then started having issues again. My brother did the bypass with resister and again it was fixed for awhile. Recently I had issues for about 3 days where it would passlock and then finally start. We replaced a couple fuses and then the final time I had ton have it towed to the dealer. They said it was the ignition switch and that seemed to work for a few weeks. Now I am getting a passlock issue every other day. Will start fine for a day or two and then suddenly I go and turn the key and all my dash lights are out and car will start and then die. For now the relearn seems to be working and I can usuallybstart the car fine in 10 mins. I know its ready when suddenly everything on the dash lig hts back up. I have spent way too much money on this car and with 4 kids can't afford much more. I'm afraid to go anywhere in fear that it will passlock and the relearn won't work which has happened before. Also the last few months I have times where the key won't turn to off so I have to press in on the button under steering column to release the key. Please any help would be awesome!!!
  • jlsummejlsumme Posts: 9
    Did they replace the ignition switch or just fiddle with it? Do your keys have the pellet resistor on them?
  • Ignition switch was replaced. Not sure about the key but I don't think it does.
  • The modification at works only on vehicles with Passlock II systems.
    1999 - 2004 Oldsmobile Alero
    1997 - 2003 Chevrolet Malibu
    1999 - 2004 Pontiac Grand Am
    A few Saturn models around the same years.

    If you can get hold of a service manual for your '97 Grand Am, find the page that shows the wiring diagram for the theft deterrent system. Scan the pages and then send them to me at Also, Find the relearn procedure in your Owner's Manual and see what they tell you to do. If the procedure is the same, then you may possibly have a variation of the Passlock II system.

    Finally, Check your key, and see if it is stamped on one side with a "+" sign inside a circle. If not, then your key doesn't have any imbedded circuits.
  • I do have a service manual that's for my car and a few others in the 97-99 range I believe. I will see if I can find a diagram and get it sent to you. I'm not sure I have an owners manual but I will check. No + on the key. Thank you for the help. I'm just at an end with this.
  • almostalmost Posts: 1
    2002 grand am/so i did bypass with no soldering option made dummy sensor followed all instructions started right away no waiting but light is still on....not flashing just on...since there was no relearn process im not sure if it worked or will have same issue later
  • Hi,

    Thank you for all the advice and assistance. I was lucky enought to be able to afford a new vehicle . I don't have the time or patience to try and deal with trying to fix the car at this point in time so I donated my car to the Breast cancer foundation. Hopefully they can make something off of it and help people at the same time.

    Have a great day and thanks again!
  • If your light is on (solid) that means that there is a fault in wiring between your bypass module and the Body Control Module. Go back to the website, and follow the directions near the end of the article for troubleshooting for wiring problems. If you find that there is an open, or a short in your wiring, move your bypass module from the Ignition area to the BCM area. Refer to the circuit diagrams at the bottom of the article. Instructions for doing the bypass at the BCM can be found at:
    You can still use your bypass module, so you won't have to solder the wires.
  • I looked through the service manual I have and there is no wiring diagram for the passlock. The service manual seems more a general manual for several make and models of gm cars. Lately since the ignition switch replacement which seemed to work for a couple weeks the car has been passlocking but usually after a few minutes all the lights come back on and the theft light flashes and goes off and car will start. Until tonight. Went to take my husband to work after a few days of no issues with the car it decides to passlock again. This time tried to do the relearn and got nowhere. Looks like I will have to tow it in somewhere just can't afford to keep fixing it temporaly :(
  • psmoorepsmoore Posts: 2
    edited May 2013
    Thanks for posting this. I will be doing the mod today. Was just wondering while driving when those lights come on my turn signals click, the electric door locks click etc. Was wondering if this will fix that too. Thanks alot!

    It's a 2004 Grand Am.
  • lovemygrandamlovemygrandam Posts: 330
    You seem to have other issues that are not necessarily related to a Passlock problem, but all of the things you describe are controlled by the Body Control Module. It is more likely that you either have a faulty BCM, or there is a wiring problem in your dashboard that is causing the BCM to do funny things. The most likely area of concern is a bad ground Splice Pack on the circuits that furnish ground to the Body Control Module. I would start by checking the integrity of Splice Pack SP202. You will need a service manual with wiring diagrams for your vehicle. The service manual will also tell you where to locate SP202. This is not an impossible task, but it will take patience to do the troubleshooting.
    Considering that you are having other problems that are related to the BCM, I would doubt that doing the Passlock mod will help.
  • psmoorepsmoore Posts: 2
    The car has been making those clicking sounds since shortly after I bought it in 2005. If I turn the turn signal on or the hazards on, the clicking quits. It is very intermittent. The techs told me it was some assembly unit and it would be like 350-400 to fix.

    I didn't get your message until after I did the mod. Cut the yellow/black made the circuit like you showed and I still have a security light. Did the 10 min and 30 min and still a light. I'm just gonna drive it with the light on and hope that it just won't stop starting. LOL My Service Engine Light Soon light has been on for 3 or 4 years and the techs can't find anything either, so I'm not worried about a light.
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