A few days ago my 2007 Volvo S60 check engine light went on. I took it to Volvo & they did an ECM update, replaced defective leak detection pump, & replaced the barometric pressure sensor. Now the light is back on HELP!!!

 

time to go back to the dealer and have them check the diagnostic codes again. Its probably a good idea for them to also give you a print out of what fault codes were found in the scan. You can also stop by a big box parts store like Autozone and borrow an OBD2 scanner to view the codes yourself (it plugs into a connector under the dash). You can then google the codes or post to the forum to get some feedback.

 

Let's hope you forgot to tighten the gas cap. Autozone or Advance Auto Parts can read your codes for free.

I would recommend getting a $15 obd2 scanner and keeping it in the glove box. You can read the codes anytime instead of panicking.

Here is a great article that can help you understand and troubleshoot Volvo check engine light yourself.

 

I agree that it is time to take it back to the dealer. Tell the dealer that you paid them fix a problem and it has returned. They should fix that.