John Deere 2019.09 – SSU: SSU Message Missing

CAN BUS communication failure where the receiving control module is not getting the required data messages from the Steering System Unit (SSU).

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 7630
• 7730
• 7830
• 7930
• 8130
• 8230
• 8330
• 8430
• 8530
• 9230
• 9330
• 9430
• 9530
• 9630
• 7185J
• 7195J
• 7205J
• 7210J
• 7225J
• Self-Propelled Sprayers
• RT Series Tracks Tractors
• T Series Tracks Tractors

1. 1

   Cycle the key switch to check for a transient communication glitch during startup

2. 2

   Check the specific fuse for the SSU in the load center (e.g., F23, F24, F26, or F51 depending on model)

3. 3

   Visually inspect the CAN bus wiring harness and connectors at the SSU for corrosion, backed-out pins, or physical damage

4. 4

   Test CAN Bus resistance across CAN High and CAN Low pins with the battery disconnected (should read approximately 60 ohms)

1. 1

   Reset and Verify

   Turn the key switch off, wait a few moments, and restart the tractor. If the code moves to 'Stored' and does not return to 'Active,' clear the code via the CommandCenter or Service ADVISOR and resume operation.

2. 2

   Fuse Replacement

   Locate your tractor's fuse panel and test the SSU power fuses. If a fuse is blown, replace it. If it blows again immediately, you have a short to ground in the SSU power circuit that must be traced and repaired.

3. 3

   Harness Repair

   Use a multimeter to verify that the SSU is receiving switched power, unswitched power, and a solid ground. If power and ground are present, check the CAN High and CAN Low lines for continuity between the SSU and the reporting module. Repair any broken wires or replace damaged connector pigtails.

4. 4

   Module Reprogramming/Replacement

   Connect John Deere Service ADVISOR to attempt to re-flash the SSU. If it will not communicate with the diagnostic tool, the SSU must be replaced by a dealer.