John Deere 1865.09 – SSU: Communication System, ELX Message Missing

This fault code is triggered when the control unit stops receiving the expected communication message from the ELX (Electronic Components Relay) circuit over the CAN bus. A missing message usually indicates a loss of power to the module, a blown fuse, a failing relay, or a drop in system voltage.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 7610
• 7710
• 7810
• 7630
• 7730
• 7830
• 7930
• 8130
• 8230
• 8330
• 8430
• 8530
• 8225R
• 8245R
• 8270R
• 8295R
• 8320R
• 8335R
• 8345R
• 8370R
• 8400R
• 9230
• 9330
• 9430
• 9530
• 9630
• 9470RT
• 9520RT
• 9570RT

1. 1

   Restart the vehicle to see if the code is an intermittent communication glitch

2. 2

   Check system voltage (battery charge and alternator output) to ensure it does not drop below 11.2V (or 10.0V depending on model)

3. 3

   Inspect fuses for the ELX circuit and the SSU in the main fuse/relay load center (often a 10A fuse like F18, F20, F21, or F02)

4. 4

   Test the ELX relay (K23, K24, or K02) by feeling if it gets warm while the key is ON

5. 5

   Inspect the CAN bus wiring and voltage supply wires to the SSU and ELX relay for chafing, melting, or loose grounds

1. 1

   Cycle Power

   Turn the key switch OFF, wait a few moments, and restart the tractor. If the code clears and does not return, no further action is required.

2. 2

   Replace Blown Fuses

   If the ELX or SSU fuse is blown, replace it with a fuse of the exact same amperage (do not use a higher-rated fuse). If it blows immediately upon turning the key, you have a direct short to ground in the harness that must be traced and repaired.

3. 3

   Swap the Relay

   Remove the ELX relay and swap it with a known-good relay of the same type (e.g., the work light relay) from the fuse panel. If the code clears and steering/communication is restored, replace the faulty relay.

4. 4

   Repair Wiring

   If the relay and fuses are good, use a multimeter to check for 12V at the relay socket and the SSU connector. Repair any broken wires or clean corroded ground terminals.

5. 5

   Dealer Intervention

   If the voltage, fuses, relays, and wiring are all intact, the SSU itself may have suffered an internal failure. Have your John Deere dealer repair as soon as possible, as SSU replacement requires dealer-level software for End Of Line (EOL) calibration and AutoTrac programming.