John Deere 002049.09 – PTQ: CAN Bus Message Fault in Main Control Module (PTQ)

A CAN bus communication error has been detected by the PTQ (Transmission Control Unit), specifically involving an incorrect message from the OIC (Operator Interface Control) software. This disruption affects the proper exchange of data between systems controlled by this module and can lead to symptoms ranging from specific transmission functions failing to a complete loss of transmission control.

• 6M Series
• 6R Series
• 7R Series
• 7015 Series
• 7715
• 7815
• 9030 Series
• 9330
• 9430
• 9530
• 9630

1. 1

   Check for other active fault codes that may pinpoint the origin of the communication error

2. 2

   Inspect fuses related to the electronic control units, specifically F9, F22, and F35

3. 3

   Visually inspect the wiring harness and connectors associated with the PTQ controller, operator interface, and main CAN bus for damage, corrosion, or loose connections

4. 4

   With power off, measure CAN bus resistance between CAN High and CAN Low (should be ~60 ohms; 120 ohms indicates a missing terminating resistor, 0 ohms indicates a short circuit)

5. 5

   With power on, check CAN bus voltages (CAN High should be 2.5-3.5V, CAN Low should be 1.5-2.5V)

6. 6

   Restart the vehicle to see if the fault is intermittent and clears on its own

1. 1

   Isolate faulty component

   If CAN bus resistance is incorrect, disconnect modules one by one and re-measure resistance to identify the location of the fault when the reading returns to normal.

2. 2

   Repair or replace wiring

   If damaged wiring or a corroded connector is found during inspection, repair or replace the affected section of the harness.

3. 3

   Replace terminating resistors

   If a terminating resistor is found to be faulty (indicated by a 120 ohm CAN bus resistance reading), replace it.

4. 4

   Replace PTQ controller

   If all other diagnostic steps have been exhausted and the fault persists, the PTQ controller itself may be faulty and require replacement. Ensure the replacement part is compatible with the specific tractor model.