Resetting P0171 code.
 

Hello everyone. I have a 2000 S40, 181K miles on it. I have a MAF sensor code of P0101, and a a fuel trim code of P0171. Car running poorly, not starting. I know that my replacement of my MAF sensor (which I will be doing in the next 7 days) may clear up the condition that caused the fuel trim code to come up (it should eliminate the P0101 code), but I have read that after I remedy the condition that caused the fuel trim code to come up that I need to RESET the fuel trim. I do not know how to reset the fuel trim. My VADIS says that I can use a VCT2000 to do it, which I understand is a computer product to read and clear codes from the ECM. However, I have an OBD II scanner that I used to pull the codes that I have. Can I use the OBD II to clear the fuel trim code (the P0171)? When I clear that code on the OBD II, does that "reset" it? Or do I have to go to something like the VCT2000 to "reset" it? Thanks for reading this. Chris

I've always reset the fuel trims by disconnecting the battery for 15 minutes or more and cleared the codes using the OBD-II scanner.

Thanks Hudini. Your advice worked. Took me some time to get back to you. Code is gone, and with new (used) MAF sensor it has stayed gone.