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Pontiac Grand Am Security Passlock Problems



  • orogleorogle Posts: 10
    edited December 2012
    removed center plug on bcm and the grey wire came loose. The wire that comes attached to the bcm . What does that wire do and how is it attached. I remember seeing some tape over the wire but didn't pay enough attention.

    can you drive the car with it loose?

  • The BCM is mounted just below the glove box behind a dashboard lower panel that can be removed. One screw and a push fastener hold the panel in place. Go to... Scroll down near the end of the page to see how to get to the BCM.

    Dick B
  • Orogle,
    Thanks to your own perserverence, you were able to help solve your situation by posting back with your observations. I winder how many people give up she they don't succeed the first time. Posting back your ohmmeter readings was the key. Glad you we we successful.
    Dick B
  • Gee, judging by the number of typos in the above message, I better refrain from trying to post messages from my tablet. I hate these tiny keyboards!!!!!
  • orogleorogle Posts: 10
    edited December 2012
    Heheheh I thought maybe it was because of a little "celebrating" of sorts.

    oh, just in case you didn't see it: can you tell me what the wire does that is connected to the bcm. I called a chevy dealer and a buick dealer and asked the service dept but neither of them had a clue.

    I noticed that it was attached to the well wall and held by some tape that was coming undone but didn't pay enough attention and certainly didn't see it actually plugged into anything. There isn't anything to unscrew to remove it.

    looked at a new gm part on ebay and it was the same single wire coming out of the bcm. Searched the internet for hours trying to find out what that wire did. No reference to it at all. Kinda reminds me of the wire hanging down on my electric door opener. Each one I have had has a wire but it is never attached to anything.

    Does that wire have a purpose? Heheheh must be good for something.

  • Beat's me what that wire is for. It's not shown on my 2002 Grand Am BCM wiring diagrams. I never noticed it when I removed my BCM. I'm assuming it's not connected to one of the three connectors???
  • orogleorogle Posts: 10
    no one seems to know. Here is a pic of it on ebay. 3.l2649

    @ small wire with a flat piece of plastic on the end of it. Doesn't look like it would snap into anything its smooth. No clip to hold it. And yet it is attached to the bcm so there must be a reason. Guess I will forgetaboutit hhehhe.

    I have another problem which probably should be in a new post but:
    Last week I went to start the car and there was darkness in the garage, the dome light wasn't on, turning the key produced no dash lights and the car wouldn't start.
    put on the multimeter to test voltage on the battery and it was fully charged.
    got out of car went into house
    went back to garage, the door was locked so unlocked door and when I opened it the dome light was on, the dash lights lit when turned the key and it started.

    @ went to the store a few days later and left the car unlocked
    and when I tried to start the car once again no power.
    @ Got out of the car and locked and unlocked the door with the key because I had no idea of what to do and no power still.
    @ Turned the headlight switch and had headlights and then dash lights and it started. I was surprised when the headlights came on.
    @ no security light flashing either time, just no power.

  • would anyone know where the passlock wire is on the ignition of a 2002 grand prix, the 2002 3.8 is different from all the other models ive looked through
  • id like to by pass the passlock but cant locate the wires i hav the whole dash apart and steering colum so i should be able to find it, i hav a white and black striped wire and solid black on one little clip and another with a light green and peach with other various other bundles anyone that has the same please help
  • Hi. Hope some one can help me out.

    I have a 2003 pontiac grand am. Car start a day before but now it just turn and won't start. I did the 10 min thing and the learning procedure but still no luck.
    My car security light is lid and stay lid when the key is turn to the ON position. After 10-15 minute in the "ON" position, the security light remains lid. shouldn't it turned off?
    I also try the learning procedure.... Turn the key on...then turn to crank the ignition..won't start. The security light goes off when its back to the "ON " position. Should the light stay lid?
    Just a note ...My security light does not flashes. Any suggestions?
  • 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
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