P0420 & P2000 on 2006 Honda Civic Hybrid

Question

My check engine light is on in my 2006 Honda Civic Hybrid.  The codes are: P0420 "Catalyst system efficiency below threshold" and P2000 "NOX catalyzer performance".  What does this indicate and how can I isolate if it is a O2 sensor or one (or both) catalytic converters?

Answer 1

P0420 Catalyst below threshold Bank 1

You can get a P2000 even if you did this code would not be valid, The best way to determine the cause is a scan tool with data, Get Bank 1 Sensor this is the downstream 02 sensor or catalytic monitor sensor , a good catalytic will have Sensor 2 above 650ml volts. a fault rear 02 sensor will read erratic