Congrats on the fix. Definitely save your daughter a breakdown by replacing the ICM.

Your Civic has two O2 sensors. The first one (before the cat) is used to determine proper air/fuel ratios whereas the second one (after the cat) functions solely to monitor emissions. The O2 sensor throwing the code is crucial for optimal engine performance and economical fuel efficiency, so you definitely want to fix it. Be aware that the code could be caused by a bad O2 sensor or by bad O2 sensor wiring.