John Deere ECU002071.09 – ECU: No Signal from Control Unit

The Engine Control Unit (ECU) has detected a loss of communication with the Chassis Control Unit (CCU). This indicates a data transfer problem where messages sent by the CCU on the CAN bus are not being received or are received intermittently. The issue points to a fault within the CAN bus network, which could be caused by an open circuit, a short circuit, or faulty terminating resistors.

• 5E Series
• 5075E
• 8030 Series
• 8130
• 8530

1. 1

   Check fuses related to the various control units (e.g., F24 for ECU and ICU, F23 for SSU)

2. 2

   Inspect the CAN bus wiring harness and connectors for any signs of damage, corrosion, or loose connections

3. 3

   Check the main ground connection from the battery to the frame (resistance should be below 2-3 ohms)

4. 4

   Perform CAN Bus Terminating Resistor Check (with power OFF and battery disconnected): Measure resistance between CAN High (yellow) and CAN Low (green) at the diagnostic connector. ~60 ohms is normal; ~120 ohms indicates one faulty/disconnected resistor; 0 ohms or open indicates a short or open circuit

5. 5

   Perform CAN Bus Voltage Tests (with power ON): Measure CAN High to Ground (should be 2.5-3.5V) and CAN Low to Ground (should be 1.5-2.5V)

1. 1

   Perform diagnostic checks

   Perform all diagnostic checks listed above. Do not proceed with part replacement until these checks have been completed to isolate the root cause.

2. 2

   Address fuse and ground issues

   If any blown fuses are found, replace them. If ground connections are corroded or loose, clean and tighten them.

3. 3

   Repair wiring

   If wiring damage is found, repair or replace the affected section of the harness.

4. 4

   Isolate faulty components

   If the CAN bus resistance and voltage checks point to a problem, and the wiring appears intact, test each terminating resistor individually. If resistors are good, begin unplugging one control unit at a time from the CAN bus and re-checking the bus resistance and voltage. If the bus returns to normal after unplugging a specific controller, that controller is likely the source of the fault.

5. 5

   Replace faulty component

   Once the faulty component (terminating resistor or control unit) is identified, replace it with a new or remanufactured part.

6. 6

   Clear fault codes

   After the repair, clear all diagnostic trouble codes from the system.

7. 7

   Verify repair

   Operate the machine to ensure that the fault code does not return and that all systems are functioning correctly.