What is the security relearn?

 

Process to "teach" the PCM that you are in fact turning the key and not trying to hotwire the vehicle.

Basically, the procedure is as follows.

Attempt to start. It'll either not start at all, or start for a half second then die.
Leave the key in run position for 10-12 minutes (til after the security light goes off).
Turn off for 30 seconds.
Repeat attempt to start.

After three 12 minute wait cycles, it should fire up.

Justin

 

I've seen that wait cycle take as long as 30 minutes.....I think it's year dependant as both '99's I've tried it on take 28 minutes for the security light to cycle

 

Ouch. 28 minutes per cycle would be a brutal wait. I've only needed to do it with an 03 and an 04 and both were quick and painless.

 

Thats good info....i plan or getting a tune here soon. SO from what i read some trucks it does this and other trucks it wont?

 

Yup....it all depends on the truck, time of day, cycle of the moon, gravitational pull, etc, I've pulled my PCM more than 30 times to try different ones (I had to bench program PCM's for awhile when my laptop died in March) and only 4 times have I had to do the security relearn (once was when I put my own PCM with no changes made to it back in...go figure)

 

I have had to do crank relearns in the past but never security relearns, I am glad I dont have that much patience.

 

Whats a crank relearn and how long does that take?

 

It is a code P0315, this is the code others have mentioned about having done at a dealer, or if you know someone with tuning software. If you have access to a tech II ( what dealers use) or something like HPTuners it only takes a min or two.