Mechanics

CODE P0420

1999 Honda CRV

Engine Performance problem
1999 Honda CRV 4 cyl All Wheel Drive Automatic 150000 miles

i have a code p0420 that says catalyst efficiency below threshold(bank 1). What is this?
Avatar
Joey little
February 15, 2009.



Usually a faulty O2 sensor will throw this code. Need to check your oxygen sensors. Follow the link below to learn how to test an oxygen sensor.

http://www.2carpros.com/how_to/how_to_test_oxygen_sensor.htm

If sensors are OK, need to flow test the catalytic converter..

Thanks for using 2CarPros.com!

Bluelightnin6
Feb 15, 2009.