John Deere 524171.19 – TCU (Transmission Control Unit) / PTA (Transmission Module IVT): Missing Info On The CAN BUS, Transmission Module IVT (PTA) or Incorrect CAN BUS Message, Direction of Travel from UIC

The UIC (User Interface Control) unit is unable to determine the value for the Direction of Travel (DDT). Because it cannot determine if the machine is commanded to go forward, reverse, or neutral, it cannot provide the CAN BUS with the relevant data. The system will typically transmit a replacement/default value to protect the transmission, which triggers this fault.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6230
• 6330
• 6430

1. 1

   Check for accompanying UIC-specific codes (e.g., UIC 305147.02 - Forward and Reverse Switches Actuated At Same Time) which point directly to a failed switch.

2. 2

   Test the reverser lever by turning the key to the ON position (engine off), moving the lever through Forward, Neutral, and Reverse, and observing the dash display to see if the gear selection is recognized.

3. 3

   Perform a neutral start circuit test by attempting to start the tractor with the reverser lever in Forward or Reverse. The starter must not engage.

4. 4

   Inspect the CAN BUS wiring harness between the steering column/armrest (UIC) and the transmission controller (TCU) for chafed wires, loose connector pins, or corrosion.

1. 1

   Disconnect Power

   Disconnect the negative battery cable before servicing electrical components.

2. 2

   Inspect the Reverser Switch

   Remove the steering column cowling or armrest cover (depending on where your reverser lever is located) to access the Direction of Travel switch/lever assembly.

3. 3

   Test the Switch

   Unplug the switch and use a multimeter to test for continuity across the switch pins in the Forward, Neutral, and Reverse positions.

4. 4

   Replace the Switch (If Faulty)

   If the switch fails the continuity test or feels physically loose/worn out, replace the reverser lever assembly.

5. 5

   Check the Harness

   If the switch tests good, use a multimeter to check the CAN BUS communication lines (High and Low) from the UIC connector to the TCU connector for continuity and ensure there are no shorts to ground. Repair any damaged wiring.

6. 6

   UIC Module

   If the switch and wiring are perfectly intact, the UIC module itself may have failed or lost its programming, requiring a dealer to reflash or replace the UIC.

7. 7

   Clear Codes

   Reconnect the battery, turn the key on, and clear the stored fault codes. Test drive the tractor to ensure the transmission engages in both directions without throwing the code.