Will P0140 code cause trouble

The P0140 code indicates an issue with the oxygen sensor circuit for the downstream sensor, typically related to the bank 1 sensor. While it may not cause immediate engine performance issues, it can lead to decreased fuel efficiency, increased emissions, and potential failure of emissions tests. If left unaddressed, it could mask other problems or contribute to further engine performance issues over time. It's advisable to diagnose and resolve the underlying issue to maintain optimal vehicle performance.