Last night, the SES light came on in my 2000 Lariat 5.4L 4x4. Went to have the code read today, and got P1405 and P1260. The 1405 should be taken care of. Found the hose from the EGR valve was off.

Now, I question the 1260. Says Theft detected vehicle immobilized. Odd thing is, my truck continues to run fine, and fires up without problem. The only thing that I can think of is I put a non-transponder key in the ignition to roll the windows up the other day. Would that kick the P1260 code, but not light up the SES light? Anything I should/could do to clear the codes besides removing the battery cables? Thanks for any help!

 

i would check the fuses, maybe reset the computer if the code is the problem and nothing else