AIR4 - Check Air Pump Operation

^ Key OFF.

^ Disconnect air supply hose from AIRB valve.

^ Check air flow at the pump outlet.

^ Does air flow increase as the engine speed increases?

YES -- Return to diagnosis by symptom for other possible causes. Diagnosis By Symptom

NO -- If equipped with silencer/filter, go to AIR5. AIR5 - Check Silencer/Filter For Obstruction If not, replace AIR pump.