John Deere 002139.09 – Front Chassis Module: CAN BUS Message Fault: Front Chassis Module

A fault has been detected in the CAN BUS message communication related to the Front Chassis Module (also designated as PTF or SCO). The Failure Mode Identifier (FMI) 09 indicates an abnormal update rate, meaning the module is not sending or receiving messages on the CAN bus network as expected. These messages may be missing, intermittent, or arriving too slowly, which prevents proper communication between the electronic control units and indicates a potential issue with data transmission or reception within the module or network.

• 6R Series
• 6150R
• 8R Series
• 9R Series

1. 1

   Restart the tractor to see if the communication fault is temporary and clears on its own

2. 2

   Visually inspect wiring harnesses connected to the Front Chassis Module for chafing, corrosion, or rodent damage

3. 3

   Inspect main chassis grounds and battery connections for looseness or corrosion

4. 4

   Verify that fuses related to the relevant controller (often labeled SCO, PTF, or similar) are intact

5. 5

   Perform a CAN Bus Resistance Check (Power Off): Disconnect a connector on the CAN bus and measure resistance between CAN High (yellow) and CAN Low (green). A healthy network reads ~60 Ohms. 120 Ohms indicates a missing terminating resistor or wire break; significantly lower indicates a short or faulty controller

6. 6

   Perform a CAN Bus Voltage Check (Power On): Measure voltage of CAN wires relative to a good ground. CAN High (yellow) should be 2.5-3.0 V; CAN Low (green) should be 2.0-2.5 V

1. 1

   Repair wiring and connections

   Address any issues found during visual inspection, such as damaged connectors, blown fuses, or broken ground wire eyelets.

2. 2

   Perform a cold boot

   If no obvious wiring or connection problems are found, disconnect the battery for a period of time to perform a cold boot and reset the controllers.

3. 3

   Isolate the faulty module

   If CAN bus resistance or voltage readings are incorrect, disconnect controllers from the CAN bus one at a time and re-check the readings. If readings return to normal after disconnecting the Front Chassis Module, the module itself is likely the problem.

4. 4

   Replace the Front Chassis Module

   If the module is confirmed to be faulty, replace it with the correct part for your machine's serial number. Have a certified dealer program the new controller after installation.