Home >> Land Rover >> 2003 >> Range Rover >> Repair and Diagnosis (Single Page) >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Self-Diagnostics - With Codes >> Diagnostic Tests >> DTC P0139: O2 Sensor Ageing Fault, Downstream Bank 1 - Plausibility >> Bosch ME7.2 EMS DTC P0139 - O2 Sensor Ageing Fault, Downstream Bank 1: Last Occurrence - Plausibility >> Possible Causes