Check Valve

The check valve, located in the pump discharge line, prevents the backflow of exhaust gas into the air pump in the even that exhaust manifold pressure exceeds air injection pressure, or the air pump fails.

1. With engine at normal operating temperature, disconnect hose from check valve and check hose opening for any sign of exhaust gas leakage. If leakage is detected, replace check valve.
2. Increase engine speed to 2000 RPM and allow it to return to idle. As engine returns to idle, check hose for any sign of leakage. If leakage is detected, replace check valve.