The P013D is a generic OBD-II powertrain trouble code. Its official definition is “O2 Sensor Slow Response – Lean to Rich (Bank 2, Sensor 2)”. This code is stored by the vehicle’s Engine Control Module (ECM) when it detects that the downstream oxygen sensor on engine Bank 2 takes too long to respond as the exhaust gas composition changes from a lean (high oxygen) state to a rich (low oxygen) state. The downstream sensor, located after the catalytic converter, is crucial for monitoring catalyst efficiency.
