New Holland DCU 19598 – DCU (Dosing Control Unit): CAN receive frame EEC1 (Driver demand, eng speed, eng torque) | too many CAN messages _ ‘P0600 Serial Communication Link

This code indicates a severe Controller Area Network (CAN) bus communication failure. Specifically, the module is receiving an abnormally high number of messages (flooding) on the EEC1 (Electronic Engine Controller 1) data frame, which triggers a generic P0600 Serial Communication Link error.

• T7 Series (T7.220, T7.235, T7.250, T7.260, T7.270)
• T8.xxx Series (e.g., T8.390, T8.410)
• T6000 Series
• FR450
• FR500
• FR600
• FR700
• FR850
• W190B
• Magnum Series (235–340, 315)

1. 1

   Verify the fault is currently active, as CAN codes can sometimes be temporarily logged during module programming or low battery events.

2. 2

   Perform a CAN bus resistance test with the battery disconnected. Measure resistance between CAN HI and CAN LO pins (Normal is ~60 ohms; 120 ohms indicates an open circuit or failed resistor; 0 ohms indicates a short circuit).

3. 3

   Inspect the CAN cable and connectors between the Engine ECU and the DCU for interruptions, corrosion, moisture, or backed-out pins.

4. 4

   If wiring and resistance are perfect, isolate the modules to determine if the ECM or DCU is hardware-faulty and flooding the network.

1. 1

   Power Down

   Turn off the machine and disconnect the battery to prevent electrical spikes.

2. 2

   Inspect and Repair Wiring

   If the resistance test failed, trace the CAN backbone. Repair any chafed wires or clean corroded connectors between the ECU and DCU.

3. 3

   Replace Terminating Resistors

   If the resistance measured 120 ohms and wiring is intact, locate the terminating resistors at each end of the CAN bus network. Replace the faulty 120-ohm resistor.

4. 4

   Isolate the Faulty Module

   If the resistance is exactly 60 ohms but the network is still flooded with messages (P0600), the Engine ECU or the DCU is likely internally shorted or malfunctioning.

5. 5

   Replace the DCU/ECU

   If the DCU is deemed the culprit, replace the module. Note: OEM documentation states that replacing the DCU requires software installation and passwords from CNH; it is not a plug-and-play repair.

6. 6

   Clear and Retest

   Reconnect the battery, clear the fault codes using a diagnostic tool, and run the machine to verify the EEC1 frame is being received properly without flooding.