Yellow lines usually mean yellow ink is showing through because another color is missing in those areas, not necessarily that yellow itself is the problem. For example, if a green area prints yellow, the cyan or light cyan nozzles may be blocked.

The most likely cause is clogged or blocked printhead nozzles. The next step is to print a nozzle check/test sheet to identify which ink channel is failing. If the missing pattern matches cyan, light cyan, or another color, that confirms the blockage.

If normal head cleaning hasn’t fixed it, the printer may need a proper service. Repeated cleaning cycles can waste a lot of expensive ink and still not clear a stubborn blockage.

If the printer is still under warranty, the best option is to take it to an authorized Epson service center. If it’s out of warranty, deeper cleaning may be possible, but it’s more involved than routine maintenance and can use a lot of ink.