John Deere 000191.09 – CCU / PTI: Missing Transmission Speed CAN Message

A communication breakdown has occurred on the Power Train CAN bus, specifically related to missing transmission output shaft speed messages (SPN 191, FMI 09). A control module is not receiving the expected transmission speed data at the correct frequency from another controller on the network, indicating an interrupted data flow.

• 6090MC
• 6090RC
• 6100MC
• 6100RC
• 6110MC
• 6110RC
• 7R Series
• 8R Series

1. 1

   Review active and stored codes for other communication-related faults to identify widespread network issues

2. 2

   Visually inspect the Power Train CAN bus wiring harness (yellow CAN High and green CAN Low twisted pair) for chafing, cuts, pinching, or heat damage

3. 3

   Check connectors at each control module (ECU, CCU, PTI/PTQ) for corrosion, bent pins, or a loose fit

4. 4

   Verify that the suspected offline controller has a stable power supply and solid ground connection

5. 5

   Test terminating resistors with power off: measure resistance across CAN High and CAN Low wires (should be approximately 60 ohms; 120 ohms indicates an open circuit)

6. 6

   Measure CAN bus voltages with key ON (engine off): CAN High should be 2.5-3.5 volts, CAN Low should be 1.5-2.5 volts

1. 1

   Repair wiring and connectors

   If initial inspection reveals damaged wires or corroded connectors, repair or replace these components first. Clear the fault codes and re-test the system.

2. 2

   Isolate faulty module

   If wiring is intact, disconnect modules from the CAN bus one at a time to see if communication is restored. The module whose disconnection resolves the issue is likely the source.

3. 3

   Update software

   Have a dealer check if any of the relevant control modules require a software update to resolve communication glitches.

4. 4

   Replace faulty components

   Replace the specific controller or terminating resistor identified as the root cause during isolation testing.

5. 5

   Perform advanced diagnostics

   If the problem persists, use specialized tools like Service ADVISOR to monitor network data and accurately diagnose the fault.