FlexFuel (Ethanol) & Auxiliary Input / Output
Internal Analog Inputs
4th Generation (2023–2025) and 5th Generation (2025+) VisiCan Displays include 2 internal analog inputs:
- Light Sensor
Located near the buttons
Displayed as AN0
Range: 0–255 - Supply Voltage Monitor
Displayed as AN1
Range: 10.0–14.4 V
External Auxiliary Input / Outputs
4th Generation (2023–2025) and 5th Generation (2025+) VisiCan Displays provide 4 external auxiliary I/O channels:
- 2 Digital / Frequency Inputs
Voltage range: 0–14.4 V - 2 Analog Voltage Inputs
Voltage range: 0–14.4 V
General Configuration of Auxiliary I/O
- Sensor data values can be viewed on the Sensor Page
(last page in the display layout) - Analog inputs are sampled at 20,000 samples per second
- Analog input values are averaged over 1/100 of the samples for stability
- 1 Digital Input is reserved exclusively for FlexFuel (Ethanol) sensor input
- 1 Analog Input is used as a 0–14.4 V voltage input
Displayed as AN2
Range: 0–255- Typical applications:
- External linear oil pressure sensor (0–10 V DC output)
- External wideband O₂ sensor (0–5 V output)
Digital Outputs
- 2 Digital Outputs
Output range: 0–3.3 V
Maximum frequency: 150 Hz- Output functionality is enabled via the optional Alarms & Outputs Add-On
- Each output can be configured independently based on parameters such as:
- Boost pressure
- RPM
- Intake Air Temperature (IAT)
- Throttle position (THR)
- Each output supports 0–90% programmable duty cycle with variable control
FlexFuel (Ethanol) Sensor Connection Details
Within the scope of this document, GM or Continental FlexFuel ethanol content sensors that provide a 50–150 Hz digital output signal (referred to as FlexFuel Sensors) can be connected to VisiCan Displays.
The sensor connector includes three terminals defined by the manufacturer.
As pin numbering may vary between sensor models, the following definitions are used instead of pin numbers:
- VCC : Sensor power supply positive (+12 V)
- GND : Sensor power supply ground (Chassis / GND)
- VOUT : Sensor signal output (Vout)
After installing the FlexFuel sensor mechanically into the vehicle’s fuel line
(manufacturers typically recommend installation on the fuel return line after the fuel pressure regulator),
make the electrical connections as follows:
- VCC → Ignition-switched +12 V
- GND → Chassis ground
Sensor Output Signal (VOUT) Connection
The VOUT sensor signal must be connected to the yellow FlexFuel sensor input wire on the VisiCan OBD cable.
Additionally, connect a 1800–2200 Ω (1.8KΩ–2.2KΩ), 1/4 W resistor from an ignition-switched +12 V source to the same junction point.
Connection summary:
- Ignition-switched +12 V → one side of the resistor
- Other side of the resistor connected to:
-
- VOUT – sensor output signal
- VisiCan yellow wire (ethanol sensor input)
Verifying Sensor Data on the Display
After completing the wiring:
- Turn the ignition on
- Navigate through the VisiCan pages using the button
- Open the Sensor Information Screen (last pages)
Displayed values:
- FQ0 → Raw frequency (Hz) from the FlexFuel sensor
- ET% → Ethanol percentage (%) in the fuel line
FlexFuel Sensor Input Test Procedure
To test the FlexFuel sensor input:
- Open the Sensor Information Screen
- Locate the yellow wire among the four auxiliary wires on the OBD cable
- Briefly touch and release the yellow wire to an ignition-switched +12 V source
(manually simulating a frequency signal)
Expected behavior:
- FQ0 and ET% values change during contact
- Random values appear on FQ0 while contact is present
- FQ0 returns to 0 when contact is removed
👉 This confirms that the VisiCan Display and FlexFuel sensor input are operating correctly.