Hello Forum,
I have received the catalyst system below thresold error (Bank 1) (P0402) twice in the last 200 miles. I am going to conduct some research on the net now, any ideas? It sounds like an oxygen sensor and the truck does idle a little rough.
One, set your newsreader to post in Plain text
Two, your bad sensor is the one after the CAT.
The sensor(s) before the CAT adjust the air/fuel mixture, and they throw a different code. The sensor after the CAT tells you that the CAT is working or not. Since the CAT itself has no moving parts, and is a costly repair, the odds favor a worn/failed sensor over a defective CAT.
I have received the catalyst system below thresold error (Bank 1) (P0402) twice in the last 200 miles. I am going to conduct some research on the net now, any ideas? It sounds like an oxygen sensor and the truck does idle a little rough.
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