John Deere 2191.09 – PL4 Module: Incorrect CAN Bus Message, Information from PL2 Control Software.

There is a data transfer problem between the PL4 control software and the PL2 control software. The reception of messages sent on the CAN Bus by the PL2 control software is intermittent or non-existent, indicating a communication breakdown typically caused by an open circuit in the CAN bus, a short circuit, or faulty CAN bus terminators.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6105R
• 6115R
• 6140R
• 6150R

1. 1

   Inspect CAN Bus wiring harness between the PL2 and PL4 modules for damage, chafing, wear, or disconnection, ensuring connector pins are secure and free of corrosion.

2. 2

   Test CAN Bus continuity with the battery disconnected using a multimeter on the CAN High and CAN Low wires to identify any open circuits.

3. 3

   Check for short circuits to ground, shorts to power, or shorts between the CAN High and CAN Low wires.

4. 4

   Verify CAN Bus terminators by measuring resistance across the CAN network (should read approximately 60 ohms; 120 ohms indicates a disconnected/faulty resistor, 0 ohms indicates a dead short).

5. 5

   Verify that both the PL2 and PL4 control modules are running the latest software versions provided by John Deere.

1. 1

   Power Down

   Turn off the tractor and disconnect the negative battery terminal to prevent electrical spikes during testing.

2. 2

   Locate Modules

   Locate the PL2 and PL4 transmission control modules (refer to the specific 6R series technical manual, such as TM410319, for exact physical locations on the transmission housing or cab floor).

3. 3

   Isolate the Harness

   Disconnect the CAN bus harness connectors at both the PL2 and PL4 modules.

4. 4

   Perform Electrical Testing

   Run the continuity and short-circuit tests outlined in the diagnostic steps.

5. 5

   Repair Wiring/Terminators

   If a wire is broken or shorted, repair the wiring harness or replace the damaged section. If a terminating resistor is faulty, replace it.

6. 6

   Reconnect and Clear Codes

   Reconnect all harnesses, reconnect the battery, and use John Deere Service Advisor (or a compatible scan tool) to clear the PL4 002191.09 fault code.

7. 7

   Module Update/Replacement

   If the wiring and terminators are perfectly intact but the code returns, the PL2 or PL4 module may require a software flash update or physical replacement.