Hi All,

Just wanted to share my recent conclusion to an intermittent P1491 that drove me insane. I read through the hundreds of threads where different people found different solutions or it was never resolved.

Backstory:

I bought a 1996 Honda Accord EX from a guy who was gonna "throw it away". Car has tons of small problems, I'm slowly working my way through them, one of them was the clogged EGR. Cleaned the ports and the EGR, code was gone for a few days, then it came back. Found this guide and tried to follow it as best I could:

https://www.2carpros.com/questions/1...p1491-on-96-lx

Everything "looked" good on mine, until it came to testing the vacuum on the EGR Control Solenoid side. This guy:



It was not consistently giving the vacuum the above guide dictated, which means when the signal went for the EGR to open, it wasn't always opening enough. No kinks or tears in any hoses, everything else was fine. So if I did city driving when the air wasn't too cold (in NorCal), it never needed the EGR. On a colder morning, when it expected the signal from eh EGR, it didn't open "enough".

Went to the local junk yard, found a clean looking assembly (Junk yard price: $15, new one from Autozone: $99 (before tax).

Light didn't come back and EGR test completed after the first drive. This also prevented the drive cycle from completing for O2 and CAT ad well.

Just wanted to pass this along.