[NormPhillips]

Hello,

On Sunday, I saw my check engine light was on my 2011 Nissan Altima 2.5s. I took it into Auto Zone and they found only one code reading: P2A00. I double checked online and spoke with friends, et cetera and they told me basically my Air Fuel Ratio (A/F) (upstream) Bank 1 Sensor 1 probably went bad.

I took it into the shop today and have performing some inspections and tests, they told me that BOTH my upstream and downstream sensors went bad.

Does this sound feasible to you? Could they both have gone bad at the same time and yet the check engine light comes on for just the upstream sensor? Or was I just taken advantage of?

Please let me know. Thanks.

[iMOTOR]

Could be both. Try resetting that code when the engine is warm; see if it comes back.

[reader50]

If either sensor failed silently - ie, kept giving a normal-looking reading, the computer may not notice. The idiot light won't come on until at least one sensor gives a reading out of sync with the rest of the engine. So a double failure is possible. Difficult to prove, unless they handed over both old sensors and you did lab tests on them.