Security light causes car to not start
06-06-2006, 04:38 PM
#1
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Security light causes car to not start 2000Trans Am A4 factory alarm
ok the security light stays on and the car wont start, i have to wait 4-5 minutes to start the car everytime i shut it off. I have to tunr the key and then turn it off then wait 4-5 minutes for the light to turn off. then the car will start. I thoguht it was the battery so i got a new battery, started up great the first time, then it started doing it again, i thoguht it might be the key, so i used the spare key i have and it did it too. I was told that it might be the ignition modual, or ignition tumbler?? any help on this would be great. Thanks
ok the security light stays on and the car wont start, i have to wait 4-5 minutes to start the car everytime i shut it off. I have to tunr the key and then turn it off then wait 4-5 minutes for the light to turn off. then the car will start. I thoguht it was the battery so i got a new battery, started up great the first time, then it started doing it again, i thoguht it might be the key, so i used the spare key i have and it did it too. I was told that it might be the ignition modual, or ignition tumbler?? any help on this would be great. Thanks
06-06-2006, 07:45 PM
#2
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It's related to that resistor in your key. The ignition cylinder is not reading the right voltage when it passes a current through your key. Therefore, it thinks you're trying to steal the car and won't start. You can try cleaning the contact points, but chances are you will have to replace the ignition cyliner and get a new set of keys. Before you ask how, I don't know. The dealer did it on my '99 and it only cost $50 because I had an extended warranty.
06-06-2006, 09:01 PM
#3
Lock cylinders are common failures. The pass key harness to the cylinder has 20 gauge wire going to it. The constant turning of the cylinder eventually the wires crack & break. Sometimes they hang on w/ a few strands of wire & cause intermittant problems also. It will get worse though.
You can search for the by pass method also. Get a set of resistors the same value as the pellet on your key.
then you wire it inline to the passkey harness at the column. This will by pass the pellet reading section of the lock cylinder & the car will start normally.
There are 2 wires. One has a 5 volt reference, the other is the return voltage back to the BCM thru the resistor. The amount of the voltage is dependant upon the amount of resistance in your key. That is basically how it works.
You can search for the by pass method also. Get a set of resistors the same value as the pellet on your key.
then you wire it inline to the passkey harness at the column. This will by pass the pellet reading section of the lock cylinder & the car will start normally.
There are 2 wires. One has a 5 volt reference, the other is the return voltage back to the BCM thru the resistor. The amount of the voltage is dependant upon the amount of resistance in your key. That is basically how it works.
06-06-2006, 09:08 PM
#4
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wrencher is right. There are 15 different resistances possible for a PASS -key system. Just take an ohm meter to the resistor on your key to figure what resistor you need.
06-06-2006, 09:32 PM
#7
TECH Resident
Thread Starter
get an ohm meter and read the PASS on the keys
and radio shack is DA place for resistors
and the shop (you know how) should be able to hook that crap up
and radio shack is DA place for resistors
and the shop (you know how) should be able to hook that crap up
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06-06-2006, 09:56 PM
#8
Originally Posted by wrencher
Lock cylinders are common failures. The pass key harness to the cylinder has 20 gauge wire going to it. The constant turning of the cylinder eventually the wires crack & break. Sometimes they hang on w/ a few strands of wire & cause intermittant problems also. It will get worse though.
You can search for the by pass method also. Get a set of resistors the same value as the pellet on your key.
then you wire it inline to the passkey harness at the column. This will by pass the pellet reading section of the lock cylinder & the car will start normally.
There are 2 wires. One has a 5 volt reference, the other is the return voltage back to the BCM thru the resistor. The amount of the voltage is dependant upon the amount of resistance in your key. That is basically how it works.
You can search for the by pass method also. Get a set of resistors the same value as the pellet on your key.
then you wire it inline to the passkey harness at the column. This will by pass the pellet reading section of the lock cylinder & the car will start normally.
There are 2 wires. One has a 5 volt reference, the other is the return voltage back to the BCM thru the resistor. The amount of the voltage is dependant upon the amount of resistance in your key. That is basically how it works.
06-06-2006, 10:30 PM
#11
Well connect an ohm meter lead to each of the metal contacts on the key. (One contact on one side & one contact on the other)
That should give you a reading. The resistance values are usually under 25,000 ohm I believe (25K)
Then you can pull the lower column apart, the panels etc. You will see a orange wrapped 2 wire harness w/ 2 small 20 gauge white wires inside. This is the pass key/ vats system harness to the lock cylinder.
You can cut into it or what ever, Just be sure you have the right harness. Air bag harnesses are yellow, so if your color blind dont f-up! J/K
That should give you a reading. The resistance values are usually under 25,000 ohm I believe (25K)
Then you can pull the lower column apart, the panels etc. You will see a orange wrapped 2 wire harness w/ 2 small 20 gauge white wires inside. This is the pass key/ vats system harness to the lock cylinder.
You can cut into it or what ever, Just be sure you have the right harness. Air bag harnesses are yellow, so if your color blind dont f-up! J/K
