Help with P0420 fault code

[armstrong_21490]

I am getting the following fault code p0420 catalyst system below threshold

I was wondering if anyone has had any dealings with this code and what is causing it?

I have cleared the code but it comes back on after a while.

Cheers

Ross

 

[mechanic69]

I am getting the following fault code p0420 catalyst system below threshold

I was wondering if anyone has had any dealings with this code and what is causing it?

I have cleared the code but it comes back on after a while.

Cheers

Ross

Ross-Tech Wiki post this info:

16786/P0402/001026 - Exhaust Gas Recirculation (EGR): Excessive Flow

Possible Symptoms
Malfunction Indicator Light (MIL) ON
Reduced Exhaust Gas Recirculation (EGR)
Reduced Power Output/Engine running rough
Increased Emissions

Possible Causes
Exhaust Gas Recirculation (EGR) Valve stuck open/leaking/faulty
Exhaust Gas Recirculation (EGR) System leaking/faulty
Wiring and/or Connector(s) from/to Exhaust Gas Recirculation (EGR) Valve faulty
Possible Solutions

Check/Clean Exhaust Gas Recirculation (EGR) System
Check/Replace Exhaust Gas Recirculation (EGR) Valve
Check Wiring and/or Connector(s) from/to Exhaust Gas Recirculation (EGR) Valve

 

[armstrong_21490]

Ross-Tech Wiki post this info:

16786/P0402/001026 - Exhaust Gas Recirculation (EGR): Excessive Flow

Possible Symptoms
Malfunction Indicator Light (MIL) ON
Reduced Exhaust Gas Recirculation (EGR)
Reduced Power Output/Engine running rough
Increased Emissions

Possible Causes
Exhaust Gas Recirculation (EGR) Valve stuck open/leaking/faulty
Exhaust Gas Recirculation (EGR) System leaking/faulty
Wiring and/or Connector(s) from/to Exhaust Gas Recirculation (EGR) Valve faulty
Possible Solutions

Check/Clean Exhaust Gas Recirculation (EGR) System
Check/Replace Exhaust Gas Recirculation (EGR) Valve
Check Wiring and/or Connector(s) from/to Exhaust Gas Recirculation (EGR) Valve

Sorry bud I just realised i had put the wrong code in the title. I've changed it now.