Air Injection: Testing and Inspection

Chart C-6 Secondary Air Injection System:

Secondary Air Injection System Wiring Diagram:

Circuit Description:

During cold starts, above 15°C (59°F), the ECM completes the ground circuit to the air pump relay which enables the air pump and integral stop valve. Air is directed to the exhaust ports whenever the engine is started. Whenever the fuel system goes to "Closed Loop," or the air pump has been "ON" for greater than 240 seconds, the ECM opens the ground circuit to the air pump relay, and the air pump is de-energized and the integral stop valve closes.

Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.

1. The ECM should energize the air pump when engine coolant temperature is greater than 15°C (59°F) and fuel system not in "Closed Loop." If any Diagnostic Trouble Codes (DTCs) are present the ECM will not energize the AIR pump.

2. The ECM should de-energize the air pump relay when engine speed exceeds 2825 RPM.

3. Air pump relay is located in the underhood electrical center.

4. Selecting "Miscellaneous Test" then AIR system on the scanner with the ignition "ON" and the engine not running should enable the AIR pump and integral stop valve. There is a possibility that the AIR pump motor will be operating, but no air is being distributed to the AIR system. The integral stop valve may not be opening or a restriction in the AIR hoses or pipes may be the cause.