Technician reported they replaced the torque motor filter on an Embraer 170 and were notified later that the B-nuts were not torqued.

Narrative

My narrative is my statement I gave to the supervisor.On Day 0; I was assigned Aircraft X. I was assigned to change the torque motor filters on the left hand pylon for the first time. I started off by removing the access panel and using the work card including the diagram pictures to successfully disconnect each part. From there; I cut the safety cable and removed the b-nut connections from the filters. This task was quite troublesome as there was a lack of sight and room. From there I disconnected the filters and crew chief tagged them. Following this; I paused for lunch and removed my tooling. Post lunch; I had then applied new o-rings to the new filters. I then was asked to dismount the work stand as a crew chief needed to look at an unrelated item needing inspection. I then safety cabled for the second time ever on the filters. I proceeded then to reinstall the panel and complete paperwork. Why on this work card is there no condition codes or inspection block.Identification: This was detected on takeoff and was rerouted back to landing. Pilot received warning messages and made the choice to land the plane.Cause:The cause of this incident was related to the difficulty of the task and the inability to see the area well. Along with that; simple mechanical error was related.Response:Plane was grounded and inspected after my shift had ended. Panel was opened up to find b nuts not tightened onto filter lines.Suggestions:On Day 0; I was assigned Aircraft X. I was assigned to change the torque motor filters on the left hand pylon for the first time. I started off by removing the access panel and using the work card including the diagram pictures to successfully disconnect each part. From there; I cut the safety cable and removed the b-nut connections from the filters. This task was quite troublesome as there was a lack of sight and room. From there I disconnected the filters and crew chief tagged them. Following this; I paused for lunch and removed my tooling. Post lunch; I had then applied new o-rings to the new filters. I then was asked to dismount the work stand as a crew chief needed to look at an unrelated item needing inspection. I then safety cabled for the second time ever on the filters. I proceeded then to reinstall the panel and complete paperwork. Why on this work card is there no crew chief or inspection block. I suggest strongly that a crew chief or operational check be put into place. Another suggestion would be to have a shadow while training for the first 6 months.