2013 Forester P0451 Troubleshooting

B737JD
Fri, 17 Jan 2025 17:04:52 +0000
Maintenance/Repairs

Hello all, this is my first post here, I’m looking to see if anyone can help me troubleshoot an emissions issue.

Specifically, I get the P0451 code every other time I drive my car when it is around 40°F outside or above. I live in Minnesota, so during the winter when it gets below 40°F the code doesn’t show up for months.

I installed a new gas cap, had the evap check valve assembly replaced, and installed a new MAP sensor, both of those are listed as the solution per Subaru troubleshooting guide.

None of these fixed the problem so I am wondering if anyone knows something I might be missing related to this issue? I’m wondering why it stops happening below 40°F and if that is telling me about something I’m not thinking about.

Thanks,
Joe

10 posts - 6 participants