I should have said Bypass & Divert instead of Bypass and Dump. Bypass is the dump.

Secondary Air Injection (AIR) System

The Secondary Air Injection system is utilized in electronic control systems to divert secondary air either upstream to the exhaust manifold check valve or downstream to the rear section check valve and catalyst. The system will also dump secondary air to the atmosphere during some operating modes.

A Secondary Air Injection Diverter (AIRD) valve (9F491) is used to direct the air either upstream or downstream. A Secondary Air Injection Bypass (AIRB) valve (9B289) is used to dump air to the atmosphere .


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Thank you that was most helpfull!

 

I might add that the two solenoids that you asked about are controlled by the computer and turn on and off engine vacuum from the tree on the upper intake manifold to the AIRD & AIRB valves in the above diagram. The valves are vacuum operated. The solenoids have 12 Volt on the red wire going to them from the PCM power relay and the other solenoid wire is grounded by the the computer to operated them.