Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › 2003 Mitsubishi Eclipse 2.4l 4G64 – P0171 + readiness monitors will not set. › 2003 Mitsubishi Eclipse 2.4l 4G64 – P0171 + readiness monitors will not set. August 21, 2019 at 3:55 am #894337 NonameParticipant HO2S is brand new, lower sensor is original, however it only detects if the catalytic converter is operational.