Even if you do the rear o2 simulation patch, you will not throw a CEL, but from what I have read and heard (Havent tried it) your ecu will not pass the readiness test so you will not pass, but still have no CEL....

I think you pretty much have to have all the sensors used for emissions. I do know you can disable the P300 CEL in the ecu and still pass, but the o2 has got to be there...... Mechanical fix, and your good to go, find a used sensor or see if you can borrow one... remember you have to have about 50 to 70 miles on the car since the last time you cleared the CEL before the ecu will pass the readiness test as well.....

 

thats why you have to also run another patch for the heater wire to it so it comes up as "ready" You can have 2 "not ready" and still pass, but the heater circuit can not be one of them