Honda Accord troubleshooting code P2138 with engine warning light on for about one day. Anything serious?

first i would find an import mechanic instead of dealer. I used a mechanic that only did honda's and toyotas. The tps sensor is the throttle position sensor----i would test that using the specs in a haynes manual, and replace it. i replaced a bad one on one of my vehicles for $20 yet it caused stalling, crazy idle surging, and NO check engine light...... One bad sensor can trigger a chain reaction