Diagnosing & Fixing Fault Code P0121: Throttle Position Sensor on 2013 GMC Yukon XL

2013 GMC Yukon XL with Check Engine Light and Brake light on

My spousal unit arrived home and promptly showed me the picture taken of the dreaded CHECK ENGINE light on our 2013 Yukon. (The parking brake is set, so that’s not a trouble light, but rather an indicator.) Last time, about… Continue Reading