Speedhut logo


Are Freedom CAN-BUS gauges are compatible with my vehicle? How can I tell if my ECU supports the CAN protocol?

Freedom CAN-BUS gauges require an ECU that supports the U.S.A GMC CAN (J1979) protocol. Freedom CAN-BUS gauges operate by receiving data from the ECU (Engine Control Unit) through the OBDII wiring. Before purchasing a Freedom CAN-BUS gauge, please research your vehicle to identify whether it will support both the CAN-protocol AND your desired gauge type output.

The easiest way to see if your vehicle's ECU supports the CAN (J1979) protocol is to check your vehicle's OBDII connector.


If the OBDII connector has wires connecting to pins 4, 5, 6, 14, and 16 then the vehicle supports the CAN-BUS (J1979) protocol.
If the OBDII connector has wires connecting to pins 2 and 10 then the vehicle does NOT support the CAN protocol.

OBDII CAN (J1979) protocol Pinout:
Pin 4 -- Chassis Ground
Pin 5 -- Signal Ground
Pin 6 -- CAN High (data)
Pin 14 -- CAN Low (data)
Pin 16 -- +12volt Battery power (not for use as gauge power)

OBDII pin out

Figure 1: OBDII Connector pinout diagram

NOTE: Freedom CAN-Bus gauges CANNOT be connected to a sender or anything that sends a raw signal.

Typically, all vehicles 2008 and newer that are manufactured by the USA, Canada, or the UK, are required to be compatible with the CAN (J1979) protocol. Some manufacturers used the CAN protocol before 2008. Not all gauge types will be supported on your vehicle's ECU. For example, not all ECUs support fuel level output.

Check with your vehicle’s dealer or the manufacturer of the ECU for information about what types of output are supported.

The following gauges will work with all ECUs with the CAN (J1979) protocol:

  • Freedom CAN-BUS Speedometers.
  • Freedom CAN-BUS Tachometers.
  • Freedom CAN-BUS Water Temperature Gauges.
  • Freedom CAN-BUS Intake Air Temperature Gauges.
  • Freedom CAN-BUS Voltage Gauges (Voltmeter).

The following gauges have limited support on ECUs with the CAN (J1979) protocol:

  • Freedom CAN-BUS Fuel Level Gauge is NOT supported on all CAN (J1979) protocol compatible ECUs.

The following gauges will only work with ECUs (with the CAN (J1979) protocol) made by General Motors (GM):

  • Freedom CAN-BUS Oil Pressure Gauges
  • Freedom CAN-BUS Oil Temperature Gauges
  • Freedom CAN-BUS Trans Temperature Gauges

How Can We Help You?

Not finding what you're looking for? Contact Us Directly