I did a swap on my truck from 4.8 to 5.3, I have a 03 rcsb but people are telling me that the anti theft got activated what should I do in this cituation I do not have a code or the key remote.

 

If your truck starts and runs then you don't have to worry about the "anti theft". Maybe clerify your problem if you have one. The more you can tell us the better we can help. If anything people are just trying to scare you.

 

No it wont crank at all with the key, only if I go direct from the starter it will crank but it wont crank over and the anti theft light stays on even if I remove my keys

 

Dealer could probably fix that. I suppose the vin isn't matching or whatever. Should be cheaper than getting a stand alone harness.

What all did you swap around? Couldn't you have just reprogrammed the 4.8s computer?

 

all I swap was the engine nothing else am using the same computer from the 4.8

 

There's a 30 minute learn procedure that might be worth trying. Otherwise check all of your connections. Key chip could be worn out too I suppose. Try another key if you have one.

1. Turn on the ignition, with the engine off.
2. Attempt to start the engine, then release the key to on; the vehicle will not start.
3. Observe the security telltale; after approximately 10 minutes the telltale will turn off.
4. Turn off the ignition and wait 5 seconds.
5. Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes; the vehicle is now ready to relearn the passlock security data code and/or passwords on the next ignition switch transition from off to crank.

Important
The vehicle learns the passlock sensor data code and/or password on the next ignition switch transition from off to crank. You must turn the ignition off before attempting to start the vehicle.

6. Start the engine. The vehicle has now learned the passlock sensor data code and/or password.
7. With a scan tool clear any DTCs if needed. History DTCs will self clear after 100 ignition cycles.

 

^don't open your door while doing the above.

 

That procedure needs to be done with the doors closed? That's very good info to know, as I could see alot of guys doing it over and over and not getting it to work....I did the procedure on my truck a few years ago and all I remember is that it took a long time lol

 

Better off rolling the window down and reaching in. It only takes 10min with a Tech 2 btw.