Mazda 6 dpf light on

Generic OBD Error Code Details for P2077
Intake Manifold Tuning (IMT) Valve Position Sensor/Switch Circuit Low
DTC Application note for Intake Manifold Tuning Valves and Intake Manifold Runner controls: Active controls are used to modify or control airflow within the engine air intake system. These controls may be used to enhance or modify in-cylinder airflow motion (charge motion), modify the airflow dynamics (manifold tuning) within the intake manifold or both.
Dont know if this is related to the DPF light coming on.

sounds like you need to get it to a garage with some diagnostics equipment dpf light may be a sighn that you need a system regen this runs the car at a set revs and temp for a set amount of time and burns of exhaust debris in the dpf fillter etc

Please note. Mazda use the DPF warning light as a service due light, about 13k after last service. Mine needed visit to main dealer, local garage couldn't reset it. From now on my Mazda 6 2.0 diesel goes to main agent for expensive servicing. Hope this helps