John Deere 516123.14 – CCU / PL1: LIN BUS Communication Issue With Battery Cut Off Relay / Battery Disconnected

The control unit detects a power-down circuit fault due to the battery being disconnected or losing communication. This condition is typically the result of loose connections, corroded battery terminals, or an internal failure within the power-down circuit (specifically the battery cut-off relay).

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6250R

1. 1

   Inspect battery terminals and wiring connections for tightness and cleanliness, ensuring no signs of corrosion, damage, or loose grounds.

2. 2

   Load-test the battery to ensure it is in good condition and providing adequate power to the system.

3. 3

   Verify the integrity of the LIN BUS wiring harness leading to the battery cut-off relay to ensure it functions correctly and has no breaks or shorts.

1. 1

   Disconnect battery

   Disconnect the battery to ensure safety before working on the electrical system.

2. 2

   Clean battery terminals

   Clean all battery terminals and cable ends thoroughly with a wire brush to remove any corrosion. Reconnect and tighten them to specification.

3. 3

   Replace battery

   If the battery failed the load test during diagnostics, replace the battery.

4. 4

   Replace relay

   If the battery and wiring harness are in good condition but the code persists, the power-down circuit fault is likely internal to the relay. You must replace the Automatic Battery Disconnect Relay.

5. 5

   Disconnect relay

   Locate the battery cut-off relay (typically mounted near the main electrical panel or battery box). Disconnect the LIN BUS connector and heavy-duty power cables.

6. 6

   Install new relay

   Install the new relay, reconnect the wiring, and clear the fault codes using a diagnostic scan tool.