Ignition switch

Tiny
TFEAR
  • MEMBER
  • 2004 CHEVROLET IMPALA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 140,000 MILES
Switched out a ignition switch but it wont reprogram the new one and security light wont go off
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Saturday, January 29th, 2011 AT 6:57 PM

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Tiny
JACOBANDNICKOLAS
  • EXPERT
The security system works like this. When you turn the key, a magnet passes close to the passlock sensor. This security hall effect sensor sends a signal through a resister to the security low reference circuit. From there, the body control module (BCM) measures the voltage and determines if it is within the previously learned voltage perameters then tells the power control module (PCM) if it should start or not. If it isn't within the learned voltage, the security stays on and the vehicle doesn't start.

Now that you have replaced the ignition switch, the body control module (BCM) needs to relearn the voltage perameters before it will tell the PCM to start the engine. To do this, first, the computer needs to be read with a proper scanner to determine what the problem is (we already know what it is, the new switch). Once the trouble code is read, the body control module needs to learn the new perameters from the new switch before it will allow it to start.

Now that I explained that, I have to give you the bad news. A dealer is the only place that has the proper equipment to perform this repair. I wish I had a better answer for you, but the BCM needs reprogramed to accept the new switch's voltage perameters.

Let me know if you have other questions.

Joe
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Sunday, January 30th, 2011 AT 7:55 AM

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