Several weeks ago, I was unable to start my Chevrolet Impala (2001 3.8 liter LS). The electronics (power windows, radio, dashboard, etc.) worked, but when I turned the key from the ON position to the START position, the car did not start -- the starter motor did not even attempt to crank the motor. There was no sound, only the orange check engine light remained illuminated. I tried several more times and eventually the car started.
The problem became worse over time, taking longer to start and occuring more often. Eventually, it would occur every time that I attempted to start the car. The problem was worse in warmer weather.
This appears to be a common problem. The problem is with the PassLock security device on the Key Ignition Cylinder (KIC) that plugs into the Key Ignition Switch (KIS). The part has a resistance value that is unique and measured by the Body Control Module (BCM). Over time, the resistor degrades and drifts, especially during warmer weather. Shown below are two views of the PassLock device:
Figure 1: The PassLock module.
Figure 2: Notice the three brown cylindrical components with colorful bands. Those are the resistors that have degraded.
To fix the problem, remove the dashboard asthetics to access the KIS. In addition to the approximately 10 thick wires going to the KIS, you should see three smaller guage wires: a black, a white, and a yellow.
Turn the key to the ON position. Leave it there for 10 minutes. Then turn it to the OFF position. Then attempt to start your car. It probably won't start and you'll have the same problem -- that's okay. Keep trying until it starts. Once it starts and is running, cut the yellow wire. Then turn off your engine. This should cause the BCM to save the new resistance (infinite resistance because you cut the wire). Now your engine should always start without problems, albeit without an element of the GM security system.
The one side effect of this solution is that the word SECURITY will remain illuminated on the dashboard while driving. Please contact me (below) if you know how to disable this.
I have successfully been driving this care for 5 years now after fixing this problem and it has never returned.
To get my e-mail address, please make a donation, whatever you feel is fair. I hope this information has saved you a bit of money and heartarche at the mechanic.