# P0420



## HeathenCruze (May 11, 2020)

I've done some reading and searching on here for this. I didnt see much of an answer. I appologize if I missed it.
Can anyone please tell me what may be the problem?
Also...we have a spot down the that floods quite often about 10-12 inches deep. I rolled thru that slowly and noticed the CEL light about 10min or so later. Could have happened sooner, IDK. Could that have caused it?
Thanks for any help.


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## BDCCruze (Jul 12, 2017)

Catalyst System Efficiency Below Threshold









P0420 Catalyst System Efficiency Below Threshold


How to diagnose, repair, and info on symptoms and causes of a P0420 engine code which means the catalytic converter is no longer performing at a normal level.



www.obd-codes.com





Possibly got some water in the exhaust system which either hosed a O2 sensor or the catalytic converter.

Check to see if the CEL is active or just history. Let the car dry overnight and you can try clearing it to see if comes back.


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