Hi All, After replacing a leaky Catalytic converter with an aftermarket universal converter. 3 weeks in I receive error code p0420. The check engine light comes on and off on it's own over the course of a year. I finally got it scanned and the auto shop says Heated catalyst not supported. They say the catalytic converter is not heating up properly hence meaning the catalyst is failed. I want to go back to the Muffler shop and convey that I know what i'm talking about before they charge me $80.00 install fee just to replace it under their 3 year warranty. Sucks to poor more money into it seeing that it caused a failure 3 weeks out of the shop. Any thoughts? My wife took the truck to them a few months after install and they simply told her without removing it that it physically looks good and for her to take it to a shop. I don't think they go any further then installing these things.

 

It may or may not be the cat. This code is a royal PITA to repair and just means this:

Catalyst System Efficiency Below Threshold (Bank 1)

Now, there are four oxygen sensors on our Monteros. Two before each pre cat, and two after. The easiest solution is to extend the downstream (after) sensors. These tell the ECU if the pre cats are doing their job correctly. By spacing them out, they pick up less exhaust fumes and send a cleaner signal. Here's a link to the two I used to solve this very problem: