My s40 failed for 3 codes p0420,p0700,&p0705 I had a hole in the exhaust fixed & the 705 netutal safety code went away and the 420 code is pending will this code go away?
Codes like these need their tests run. Google them or seek the glossary and possible causes at enginecodes.com. codes that come and go have reasons why they set. they may return in some cases because healing is not something the vehicle can do.
since you fixed he hole in the exhaust, you may have fixed the problem. as long as you are not having drivability problems, turn the code off and see if it comes back. if so then you still have an issue.
The hole in the exhaust system was most likely allowing fresh air to be drawn in the exhaust system and past the downstream oxygen sensor. The computer saw this as a fluctuation of exhaust gasses which triggered the P0420 code. With the hole fixed the computer must run several diagnostic cycles before it determines the problem is fixed. Usually takes about a week of normal driving. Once this happens the check engine light will go off and the catalytic converter readiness monitor will set. Then you can pass inspection. While you're waiting for this to happen keep your gas tank between 3/4 and 1/4 full. No more and no less. This way all the tests will run, and you'll be good to go. HTH. -Jim
And you can save a week, by following the code read, pinpoints, and resetting the power supplied to it, a relearn would take a day . lets see what actually happens....let us know how it actually goes
Looking for a Used S40 in your area?
CarGurus has 749 nationwide S40 listings starting at $1,450.
Search Volvo S40 Questions
Volvo S40 Experts
Related Models For Sale
Used Cars For Sale