ibiza fr PD130 2006 Glow plug + engine light + limp mode HELP ?

[clarkyb182]

hello i have a seat ibiza fr PD130 2006, car was sitting over night turned it on the next morning to find check engine light on glow plug light blinking & limp mode

code comes back as P0726 engine speed input but the car starts perfectly fine on the key ? doesnt stall and all else seems perfect

any idea ? thanks