2001 V70 EVAP Codes Reoccur After Repairs

a_e_cole · Post by **a_e_cole** » 02 May 2014, 06:44

I am getting engine codes P0446 (EVAP Control System Vent Control Circuit Malfunction) and P0458 (Purge Control Valve Circuit Low) I have replaced the shut off valve and the canister purge valve with new original parts. The codes come back instantly on start up after they are cleared. What else could set these codes. Some back ground information in case it may be relevant. The fuel pump and oil trap have been replaced in the past. Car runs fine and have not worried to much about these codes in the past. However now that I have moved I have to pass inspection. I hope some one has insight on this before I have to start chasing wires and replacing lots of hoses. This is a non turbo engine. From all the research I have done there seems to be a difference in the EVAP systems.

Post by **coflynn** » 03 May 2014, 07:40

For lack of anything useful... have you considered getting a VIDA/DiCE setup? It would (probably) be invaluable in seeing actual diagnostic information beyond just the code itself. That being said I have no idea about your specific problem. When sorting out my own EVAP problems (which was simply a leaky gas cap & had different codes anyway so it's not your problem) it was very useful to confirm things.

a_e_cole · Post by **a_e_cole** » 05 May 2014, 13:02

After tracing every hose on the system looking for leaks and replacing a few suspicious lines. I reset the codes and noticed something odd. After clearing codes again I noticed the check engine light came on instantly on start up. That made me a think it could have been electrical since in was instant and not enough time to pull vacuum on the system. After tracing wires I found a chaffed wire that was grounding out. Taped it up and replaced lots of plastic shielding. Still got the codes and after further checking I found where the short had blown the fuse labeled 'PCV / VALVES'. I replaced it and the codes stayed gone. At state inspection it did not pass for the evap system their computer shows 'not ready'. The tech said to drive it for a week and they should clear on out that it takes time to fully leave the system even though no CEL is on. I hope my experiences can help some one out that is chasing the same issue.

Post by **abscate** » 09 May 2014, 09:00

The EVAP cycle on Volvo is one of the longer ones - mine take almost 100 miles to go READY before I can pass NY emissions. (MIL or CEL must be out, all cycles READY)

My VWs routinely go ready in about 10 miles - I just did O2 sensors on my VW, reset code, drove home 7.5 miles and left it back at shop for inspection with all systems READY. Passed all inspection tests.