Need Help With P0420, P0430 and P0325

[PenelopesEdge]

My 2013 Edge with the 3.5L and 119k miles has the following codes:

P0420 - Catalyst Efficiency Less Than Threshold Bank #1

P0430 - Catalyst Efficiency Less Than Threshold Bank #2

P0325- Knock/Combustion Vibration Sensor A Circuit.

Ive been doing some reading on the first 2 codes and it seems to be either O2 sensors or the Cats. Some people have said theres some flaws with this particular exhaust system and these codes are VERY common. I dont have a lot of money so replacing the Cats would be financially impossible for me currently. Do you think i could replace the 2 O2 sensors and be okay?

Second, the Knock Sensor code im assuming is just the sensor is bad. Could this code possibly cause the 0420 and 0430 codes or are they unrelated?

Just trying to get a better understanding and some helpful advice on how to approach this. Any advice would be welcome! Thanks in advance!

[enigma-2]

Pulled this off another forum. 

 

Yes an exhaust leak within 24 inches after the downstream O2 sensors can trigger P0420 and P0430 codes. A flex joint in the exhaust system sometimes only leaks when the power train is under load as the engine twists on it's mounts.

 

May be worth checking out..

 

[DILLARD000]

Have the OxSensors ever been renewed; should be changed every 100kMiles\12years as the chemical coating wears out?

The KnockSensor (glorified 2wire microphone) issue could be a loose connector or broken\worn\mousechewed cable;

that sensor is bolted to the top of the engine block in the "V" under the IntakeManifold;

inspect that Cable+HarnessConnector.