1999 Chevy Blazer Passlock II Problem


I have had an intermittent “no start” condition on my Chevy Blazer for approx. 2 years. Without any ryme or reason it will start and then shut off the flow of gasoline to the injectors. (something I think it’s supposed to do if it thinks it’s being stolen) I wait ~ 10 minutes and the vehicles starts. I know it’s the passlock system because the security light in the dash is lit. I have NOT had the problem diagnosed by a licensed mechanic, but I HAVE done a ton of research on the subject myself. I have no other starting issues with the vehicle. It has been very well maintained and has 85K miles on it. This intermittent problem is driving me CRAZY! Can someone please help me. I’m desperate!


You may have a faulty key chip that the computer recognizes ‘intermittently’.
Perhaps damaged? Have you tried alternate programmed keys?

You could try reprogramming the security system to see if that helps.


The key for my 99 Blazer does NOT have a chip in it. I believe the “sensor/chip” is in the key cylinder. How can I re-program the security system in my Blazer?


You MAY have answered you own question in your 2nd sentence. (Wear with age)

I suspect a dealer has to program this as I think it is regulated by the FCC. (radio frequencies) Here in Canada it is called the CRTC.


The use off a Tech2 diagnostic scanner wiil be a valuable tool in solving this problem. I could not do anything to advise on this concern without the data from the Tech2. the Tech2 is GMs scanner for OBD11 systems. Has programning features. You can down load data from a PC (driveability,transmissiom security)into the Tech2 then transfer the data to the appropriate computer in the car. Specific programs for Passlock 2 concerns