Circuit/System Description

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.

For an overview of the component/system, refer to: Heated Oxygen Sensor Description and Operation

Circuit	Description
Signal - Terminal 3	The control module input circuit has an internal resistance connected to ground.
Signal - Terminal 4	The control module input circuit has an internal resistance connected to 5 V.

Component	Description
B52 Heated Oxygen Sensor	When the engine is started, the ECM operates in an open loop mode, ignoring the HO2S signal voltage while calculating the air to fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 40 to 1, 050 mV. Once sufficient HO2S voltage fluctuation is observed by the ECM, closed loop is entered. The control module uses the HO2S voltage to determine the air to fuel ratio. An HO2S voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An HO2S voltage that decreases toward 0 mV indicates a lean fuel mixture.
K20 Engine Control Module	The control module controls a series of actuators to ensure optimal engine performance. The control module does this by reading values from a variety of sensors, interprets the data and adjusts the engine actuators accordingly.

Component

Description

B52 Heated Oxygen Sensor

When the engine is started, the ECM operates in an open loop mode, ignoring the HO2S signal voltage while calculating the air to fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 40 to 1, 050 mV. Once sufficient HO2S voltage fluctuation is observed by the ECM, closed loop is entered. The control module uses the HO2S voltage to determine the air to fuel ratio. An HO2S voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An HO2S voltage that decreases toward 0 mV indicates a lean fuel mixture.

K20 Engine Control Module

The control module controls a series of actuators to ensure optimal engine performance. The control module does this by reading values from a variety of sensors, interprets the data and adjusts the engine actuators accordingly.