2001 V70 NA DTCs

dchapman · Post by **dchapman** » 04 Apr 2025, 09:55

I have a CEL on my 2001 V70 Base NA. I pulled the codes and I'm getting P0442 and
P0420. Last year I replaced a downstream O2 Sensor to fix a light. Now this.If I clear them it takes a couple days to come back. Thanks for any help you folks can offer!

David C

dikidera · Post by **dikidera** » 04 Apr 2025, 09:59

Either bad cat or some fueling issue like a vac leak. Like for example a crumbled or disconnected evap hose which p0442 refers to.

Post by **jonesg** » 05 Apr 2025, 01:53

I covered my tailpipe with duct tape and put compressed air up the pipe, I could hear air leaking from the cat.
Pulled the cat and welded up the holes, no more CEL.
First time in many years its been clear of codes.

Smoke test it from the intake too, stuff a rag in the airbox, inject air at the intake manifold.
See homemade smoke testers on youtube.