The two officers were arrested last week and are understood to have sent drivers to certain inspection centres where vehicles would be guaranteed to pass their MOTs in exchange for a payment of €75 per car.
According to newspaper Correio da Manhã the officers also promised that the vehicles would not then afterwards be stopped in road traffic operations.
The pair await trial in freedom and face charges of passive corruption, abuse of power and personal favouring.
One of the officers works for the National PSP Bureau while the other works for the Lisbon Metropolitan Command. Neither have, according to the newspaper, yet been suspended from their jobs.
A vehicle inspector whose job it was to approve unfit vehicles and emit a fake certificate in exchange for between €20 and €50 has also been detained in connection with the set-up.
The crimes took place between June 2014 and this month.
The two officers and the inspector were detained by colleagues of the PSP’s Criminal Investigation Unit and also saw searches carried out on their homes and on a garage.
One of the inspection centres involved is a CIMA centre in Poço do Bispo, Lisbon.