Circuit/System Description

WARNING: This page is about a different car, the 2019 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.

The fuel level sensor changes resistance based on fuel level. The Fuel Pump Driver Control Module monitors the signal circuit of the fuel level sensor and sends the signal information to the Engine Control Module (ECM) for all further handling. The ECM uses this value in order to determine the fuel level. When the fuel tank is full, the resistance of the fuel level sensor is low and the ECM senses a low signal voltage on the signal circuit of the fuel level sensor. When the fuel tank is empty, the resistance of the fuel level sensor is high and the ECM senses a high signal voltage. The ECM uses the signal circuit of the fuel level sensor in order to calculate the percentage of remaining fuel in the tank. The Fuel Pump Driver Control Module sends the fuel level percentage via High Speed CAN-Bus to the body control module (BCM). The BCM then sends the fuel level percentage via Low Speed CAN-Bus to the instrument cluster in order to control the fuel gauge.For an overview of the component/system, refer to:Instrument Cluster Description and Operation

Circuit	Description
Fuel Level Sensor Signal	The control module input circuit has an internal resistance connected to 5 V.
Low Reference	Grounded through the control module.

Component	Description
B46 Fuel Level Sensor	The resistance of the sensor changes with fluid level.
K20 Engine Control Module	The K20 Engine Control Module monitors the fuel level sensor. When the fuel tank is full, the resistances of the fuel level sensor is low and the control module senses a low signal voltage on the signal circuit of the fuel level sensor. When the fuel tank is empty, the resistance of the fuel level sensor is high and the control module senses a high signal voltage. The K20 Engine Control Module converts the signal input to a fuel level value.

Component

Description

B46 Fuel Level Sensor

The resistance of the sensor changes with fluid level.

K20 Engine Control Module

The K20 Engine Control Module monitors the fuel level sensor.
When the fuel tank is full, the resistances of the fuel level sensor is low and the control module senses a low signal voltage on the signal circuit of the fuel level sensor.
When the fuel tank is empty, the resistance of the fuel level sensor is high and the control module senses a high signal voltage.
The K20 Engine Control Module converts the signal input to a fuel level value.