CT3400TW and vehicle security light

Hi All, I installed a ct3400tw in my 2002 Silverado 5.3l about 10 years ago. It has worked excellent until this morning. When using the remote, it starts buy runs only for a second then stops, it tries 2 more times as it should but does the same thing. The security light is now on, the security light does shut off after about 10 minutes and then I can start as normal with the key and it seems to run fine. Any ideas ??

I also now recall that occasionally after using the remote to start the vehicle the Security light might come on while driving. The engine would still run though.

Sounds like a Passlock2 issue. What did you use as a bypass?Soldering is fun!

OMG...that was a long time ago I'm not sure. Do you think the bypass might be the issue?

Now I'm thinking it might be the immobilizer key fob as when i use my other key with the master key fob the vehicle starts

With Passlock2, there is no transponder chip in the ignition key. It uses a resistor value inside the ignition cylinder switch assy. They are known to go bad causing the symptoms you mentioned ( no start, Security light and a 10 minute time-out period ). Ten years ago, the most popular way to bypass this immobilizer system was with relays and a resistor that had the same value as the one inside the ignition cylinder. Over time the bypass resistor value can change enough to cause problems, too. Especially in cold weather. It would be best to check to see what was used to do the Passlock2 bypass. There are newer Passlock2 bypass modules that handle it through DATA going right into the J1850 wire at the Pin 2 of the OBD2 connector. These are very reliable in all types of temperatures over many, many years.Soldering is fun!

Would i need to remove the original resistors and relays before adding the new bypass?

Probably best. Keep things clean plus you will need to use the GWR wire for the new bypass.Soldering is fun!

Thanks for the replies !! Can you recommend a DATA brand for my vehicle and a link for installation ? Thanks again

So it all seems to be quite sporadic. I tried the remote today and it worked fine, key starting worked as well using both the master and clone key fob. Does this make it even more likely that the bypass is failing?