P0418 — Secondary air injection system relay "A" circuit

Code P0418 is a standard OBD-II diagnostic trouble code: Secondary air injection system relay "A" circuit.

In our record, P0418 is reported most often on Toyota and Subaru vehicles , against engine and electrical failure patterns , across 2005–2013 model years. Toyota alone accounts for 88% of them.

In ProblemsByVin's analysis of the NHTSA owner-complaint record, owners cite P0418 across 8 vehicle failure patterns. Diagnostic codes in complaints are reported by owners and are unverified — they point to where this code shows up, not a confirmed diagnosis. Open a page below for the full pattern (symptoms, mileage, repair costs owners cite).

Vehicles where owners report P0418 8 patterns

2013 Toyota Tundra

electrical — Secondary Air Injection (SAI) Pump System Failure

2012 Toyota Tundra

engine — Secondary Air Injection (SAI) System Failure — Pump and Valve

2012 Toyota Tundra

powertrain — Secondary Air Injection System Water Intrusion / Relay & Valve Failure

2012 Toyota Tundra

electrical — Secondary Air Injection System Malfunction

2011 Toyota Tundra

electrical — Secondary Air Injection System Failure

2007 Toyota Tundra

engine — Secondary Air Injection System Failure (Air Pump & Valve)

2006 Subaru Impreza

engine — Secondary Air Injection (SAI) system valve failure

2005 Toyota 4Runner

engine — Secondary Air Injection System Failure (Relay/Pump/Valve)

Codes are pulled from what owners wrote in their NHTSA filings — they're allegations, not a shop diagnosis. Always confirm with a live scan. Browse all diagnostic codes →