SUPPLIED NEW Parts delivered next working day. CALL: 0208 462 2543 Email: info@emissioncontrols.co.uk The secondary air pump is the main component of the secondary air system. The pump can be prone to failure which is generally due to the secondary air non return valve sticking and allowing condensation from exhaust fumes to enter the pump. The electrical reversing valve can cause problems as well and should also be checked for correct operation as this operates the secondary non return valve. When changing the secondary air pump it is advisable to also check all components and hoses.