Originally Posted by Inaccurate

Do a ecu reset by disconnecting your battery for a few seconds. Remember that you will need the code for your radio and Nav after doing the reset.

If the cel comes back, get the diagnostic code. Post again with the diagnostic code after doing a rest. We can advise more from there.

The angled defoulers supplied with the PCD are nearly perfect or possibly absolutely perfect. There have been just a very, very few people on Acuarazine that have had CEL with the Version 2 PCD.

In my opinion, these very few cases *might* had been from O2 sensors being damaged during the PCD install, and not the fault of the defoulers. The sensors are delicate and easily damaged. Hitting on the wrench to break loose the stubborn sensor will send damaging vibrations to the sensor. Get oil (anti-seize?) on the business-end of the sensor and the sensor is compromised. Drop the loose sensor hard on the concrete floor and it is compromised.

Originally Posted by josiel

if i install the defouls do they go on all 3 sensors

Originally Posted by josiel

i didnt install any defoulers will that be the problem?

Originally Posted by csmeance

If you just installed the PCD without the defoulers, I'm 99% sure that's the issue causing the CEL. The car sees elevated levels of emissions and throws a CEL for "02 sensor" or for "catalyst efficiency below threshold"