Just bought a 2000 Honda civic lx 4 door automatic for my girlfriend... 250,000 taken very good care of. exterior 9/10, interior 10/10. We live in AZ so we do emissions and all. There was no CEL on the car when we bought it. did a full tune up on it, wipers, etc... well 40 miles goes by and i get a p040 code for the new CEL. I cant find anything on this. anyone have any ideas? And yes, that is the full CEL code it gave.

 

Check your power steering fluid, and reset the ECU. See if the code returns. If it doesn't, great. If the CEL comes back on, pull the code again, but use the jumper trick instead of a scanner. Info is in the FAQ's sticky.

 

I cleared it and it has yet to light back up. PS fluid looks good. Thanks for the heads up!

 

incase you werent able to find it man

https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/how-pull-cel-d4-srs-abs-codes-code-lists-1901557/

 

P040 is not a code. There's one digit missing.

 

Thanks for the heads up folks. Tested it with a Snap On OBD tester and got some really good information. Needed new o2 sensor. Would work 98% of the time but would not report 2% of the time. Why the CEL was lit. Still did not fix my other problem that I didn't mention, the Idle. I have done a near full tune up. Changed cap, rotor, wires, plugs, airfilter. Have the fuel filter, will do that tonight. But after the car warms up it idles at about 250-500, very low, to where I think its going to die. This does it when car is in gear, park and neutral when it warms up. Car is 100% stock automatic D16Y7. Next step is to clean IACV and adjust idle if necessary. Any one else have $0.02?

 

iacv and adjust cable.