Code : P0491
Make : FORD
Description : P0491 FORD Secondary Air Injection System Insufficient Flow Bank 1
Possible causes :
– Secondary air pump with no or low air flow
– Secondary air bypass solenoid leaking /blocked or stuck open /closed
– Secondary AIR air hose restricted
– Secondary air vacuum hoses restricted or leaking
Solutions :
– Carry out a Reset via CarDiag
– Choose a better quality fuel
– Check that the tank cap is securely closed
– Check the oil level and add more if it is lower than MAX
– Restart an Automatic diagnostic via CarDiag
– If the fault persists, you can check the “Possible causes” listed above : visually inspect (by yourself (tutorials to come) or by a professional) the wiring harness and the associated connectors, check for damaged components, and look for broken, bent, pushed, or corroded connector pins.
