Code 0420

CHRIS CHUMLEY

MEMBER
2006 CHEVROLET HHR
2.2L
4 CYL
2WD
AUTOMATIC
86,000 MILES

The 0420 code keeps throwing. I have replaced the catalytic converter and both 02 sensors. What can it be?

Thursday, November 7th, 2019 AT 6:39 PM

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

I attached the diagnostic information that gives the detail about the other items to check. The largest cause of this (after the sensors and cat) is an exhaust leak. It could also be a wiring issue but check out the diagrams and let me know if you have questions. Thanks

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