Code P0411 secondary air flow check valve

Tiny
DAVE COWARDIN
  • MEMBER
  • 2012 CHEVROLET COLORADO
  • 3.7L
  • 5 CYL
  • 4WD
  • AUTOMATIC
  • 197,000 MILES
I recently replaced the exhaust manifold catalytic converter on my truck. While doing so I had to move the secondary air flow check valve so I had room to pull the manifold. When I disconnected the hose that leads to the actual secondary air pump there was no carbon build up on the exhaust side of the check valve yet where the check valve attaches to the manifold it had carbon buildup on both ports going to the valve. I am now getting the P0411 code for the check valve. I read on the Trailblazer side of this site of a way to clean the manifold port leading to the check valve where the gasket goes between the manifold and the valve. Would I use a soft small bristle brush to clean the 2 ports and how do I follow the cleaning course up into the manifold if I can? Is it possible to clean the check valve from the manifold port side also?
Monday, March 2nd, 2020 AT 1:49 AM

1 Reply

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

Getting inside the head is tough to access. You may need to use a coat hanger to fish around inside the head for the passages. If not, the head would have to be removed and tanked to get the carbon out of the passages. That is in a worse case scenario.

Roy
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Monday, March 2nd, 2020 AT 5:06 AM

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