Air carrier technician reported failure to check the tire pressure after completing a main gear tire replacement. Aircraft returned to the gate for another tire change.

Narrative

On Day 0; at approximately XA:50hr; in ZZZ; another mechanic and I approached aircraft X to perform the Two-Day Inspection. I found No. 3 tire was worn to limits. While the other mechanic went to grab the tire cart and tools; I started prepping for the removal of the worn tire. On Day 1; at approximately XB:05hr to XC:15hr; I removed the worn tire and installed the new tire with the assistance of the other mechanic. After the installation of the new tire; I cleaned up the area and picked up any loose safety wires and trash that came from the new tire. With everything cleaned up; I went back to the truck; resulting in not checking the new tire for the correct pressure as stated in the AMM (Aircraft Maintenance Manual). During the maintenance; I did not have the reference pulled out; rather relying on memory alone; which resulted in forgetting the last step in the manual. As result of not checking the pressure on the new tire after installation; Ops reported to the crew that the #3 tire looked low during push back at approximately XD:36hr. Line maintenance was called and found the tire was at 60psi; below the required specification. This caused the plane to be grounded; and both right tires had to be changed as per the AMM. Maintenance reported to have completed the removal and installation of both tires at XE:58hr. The aircraft departed thereafter.