I'm having issues receiving data from a 3.3 volt logic level R503 Fingerprint Module that is sent via it's Tx pin using UART. The logic levels are converted to 5 volts using a bi-directional converter. When not plugged into the converter, the logic levels from the module are 2.6 volts in the high state and 0 volts in the low state (See image 1). When the sensor is connected to the converter, the logic levels from the module, measured on the low side of the converter, are 2.6 volts in the high state and 1.2 volts low state (See image 2). This results in the output from the converter to NOT be driven all the way low, therefore preventing the microcontroller from receiving any data. See image 3 for output from the level converter.
I am unable to determine the cause of this issue. I have checked and used different cables, connectors, and power supplies. This issues is also present and can be reproduced on the only 2 sensors I have. Any help would be greatly appreciated!
Image 1: 1 volt/div - Tx pin Not connected level converter
Image 2: 1 volt/div - Tx pin connected to level converter. Measurement is taken at the low side of the converter.
Image 3: 2 volts/div - Tx pin connected to level converter. Measurement is taken at the high side of the converter.
EDIT: Added schematic