Fuel Level Gauge

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 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. The ECM sends the fuel level signal via serial data to the BCM. The BCM then sends the information via serial data to the instrument cluster to display the fuel level.

The instrument cluster displays the fuel level based on the information from the ECM. If the fuel level falls under 11% the instrument cluster will illuminate the low fuel level indicator. The fuel gauge defaults to empty if:

The ECM detects a malfunction in the fuel level sensor circuit.
The BCM detects a loss of serial data communications with the ECM.
The instrument cluster detects a loss of serial data communications with the BCM.