Codes P0412 & P0418

2008 CHEVROLET TRAILBLAZER
6 CYL • 4WD • AUTOMATIC
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BILLK
  • MEMBER
  • 16 POSTS
Received P0412 & P0418 codes. Scanner states Secondary Air Injection system Valve A circuit malfunction and Secondary Air Injection system Relay A circuit malfunction. I have not been able to determine where to begin to look for what the problem is.

Thank you,
Bill Kennedy
Jun 28, 2011 at 4:14 PM
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DOCFIXIT
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 18,828 POSTS
The air injection relay #55 is probably faulty causing both of the codes. Here is a guide to help check it and the location of the relay as well

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit


Check out the diagrams (Below). Please let us know what you find.
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Jun 28, 2011 at 5:47 PM