About once a year, I get the P20EE CEL / code. In the past I the fix has been to change either the upstream or the downstream NOX sensor. My questions are-
1- How do I test a NOX sensor to be sure which one is bad?
2- How do I stop them from going bad so often?
Its not that replacing them is so much work, its that they are $300 a piece, and I would like to know for sure whats bad before wasting that much money.
1- How do I test a NOX sensor to be sure which one is bad?
2- How do I stop them from going bad so often?
Its not that replacing them is so much work, its that they are $300 a piece, and I would like to know for sure whats bad before wasting that much money.
Aug 25, 2026 at 1:21 PM
