DTC P0130: Closed Loop Rationality: Description

When the vehicle is first started, the engine operates in an Open Loop operation, ignoring the heated oxygen sensor signal and calculating the air/fuel ratio based on inputs from the Engine Coolant Temperature (ECT), the Throttle Position (TP), and the manifold absolute pressure (MAP) sensors only. The Powertrain Control Module (PCM) will begin by using the Heated Oxygen Sensor (HO2S) signal for controlling the fuel delivery (Closed Loop) when the following conditions are met:

• The engine has run a minimum amount of time based on ECT at engine start up.
• The Heated Oxygen Sensor 1 (HO2S 1) has a varying voltage output showing that the sensor is hot enough to operate properly.
• The ECT has increased a minimum amount based on the ECT at engine start up.