John Deere 000190.19 – EPC: Missing Engine Speed CAN Message

The Electronic PowrQuad Controller (EPC) has lost communication with the Engine Control Unit (ECU) over the Power Train CAN bus. Specifically, the EPC is not receiving the required engine speed data from the Engine Module Engine Speed Rear Chassis (CCU). This communication is critical for proper transmission operation, and its absence triggers the fault code.

• 6130
• 6230
• 6330
• 6430
• 6530
• 6630
• 6830
• 6930
• 7130
• 7230
• 7330
• 7130 Premium

1. 1

   Visually inspect the wiring harness and connectors between the Engine Control Unit (ECU) and the Transmission Controller (EPC) for chafing, corrosion, or loose connections

2. 2

   Check for other communication-related fault codes on the network to determine if the issue is isolated to one controller or is a wider network problem

3. 3

   With battery disconnected and ignition off, measure resistance between CAN High and CAN Low at a diagnostic connector (should be approximately 60 Ohms; 120 Ohms indicates a failed or missing terminating resistor)

4. 4

   With ignition on, measure CAN bus voltages: CAN High (Yellow wire) should be 2.5-3.0 VDC, and CAN Low (Green wire) should be 2.0-2.5 VDC

1. 1

   Verify the fault

   Start the machine and check if the fault code is active. Note any operational issues, such as the transmission defaulting to a 'come-home' mode.

2. 2

   Test and replace terminating resistors

   If the CAN bus resistance measured 120 Ohms, locate and test the individual terminating resistors. They should each measure 120 Ohms. Replace any that are out of specification.

3. 3

   Test CAN bus wiring

   Disconnect the ECU and EPC and check for continuity on the CAN High and CAN Low wires between the two controllers. Check for shorts between the CAN wires and to power or ground. Repair or replace damaged harness sections.

4. 4

   Isolate faulty controller

   If wiring and resistors are good, disconnect controllers from the CAN bus one at a time to see if the network's electrical properties return to normal. The EPC is often the more likely culprit when it logs this fault.

5. 5

   Replace faulty controller

   Replace the ECU or EPC if determined to be the source of the fault. Clear the fault codes and operate the machine to verify the repair.