Acura Engine light still on after 02 sensor replaced

The diagnostic came out and replaced 02 sensor. Passed smug test. Light went on the day after. Should I go back to mechanic and ask for my money back???

Thank YOU!!! for your feedback!

The O2 sensor is about the biggest whipping boy that can be found when it comes to explaining why a Check Engine light is on. There are any number of things that can cause an O2 sensor code.

It would help to know what the original diagnostic code was and at this point it’s unknown whether the CEL is on for the same reason or not.

That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.

A CEL code will never say "replace O2 sensor. It may say I am seeing something odd about that O2 sensor. It may not be the sensor.

Thank you all for your help.
So I went back 2 mechanic. His estimate says:
New Code PO401,
EGR Insufficient + F low,
EGR needs to clean,
$400.00 cost.
So, I already paid $380 to replace 02 sensor, now, cleaning the EGR $400.00?
Thank you!

Thank you for your help.
So I went back 2 mechanic. His estimate says:
New Code PO401,
EGR Insufficient + F low,
EGR needs to clean,
$400.00 cost.
So, I already paid $380 to replace 02 sensor, now, cleaning the EGR $400.00?
Thank you!

What was the original code that led to the replacement of the O2 sensors? B/c, while ok4450 noted that the O2 sensor is a big whipping boy for many codes, an egr code is not one them. It is entirely possible that you have two completely different things going on.

An EGR code normally has people replacing the egr valve - and this often does nothing b/c it often isn’t the EGR valve that is the problem.

Read this: http://www.obd-codes.com/p0401

and when the shop suggests a remedy ask them if they checked the sensor, checked the solenoid, cleaned the passages, actually tested the egr valve both electrically and mechanically. If they didn’t do these things first I’d go to another shop.