New Holland ENG 3096 – Engine Control Module (ECM): Tier 3: ECM Bus Off on CAN A / Tier 4a: ECM Bus Off on Vehicle CAN

This code indicates a critical communication failure on the Controller Area Network (CAN). Specifically, the engine controller has detected an excessive number of transmission or reception errors on the vehicle's main CAN bus (CAN A). To prevent corrupting the entire network with faulty data, the controller's internal transceiver has forced itself into a "Bus Off" state, effectively disconnecting the engine from the rest of the vehicle's communication network.

• T7 series
• T8 series
• T900 series
• CR9090
• CX8080
• CX8090 Elevation
• L220
• SR175
• Magnum 235 - 340 (Series 4)

1. 1

   Verify battery voltage is within normal operating range (12V-14V) as low voltage can cause modules to drop off the CAN bus.

2. 2

   Inspect ECM connectors and main vehicle CAN bus wiring harness for chafing, pinched wires, moisture intrusion, or bent/corroded pins.

3. 3

   Perform CAN Bus Resistance Test: With ignition OFF and battery disconnected, measure resistance between CAN High and CAN Low pins at the diagnostic port (Healthy = ~60 ohms; ~120 ohms = open circuit/failed resistor; ~0 ohms = short).

4. 4

   Perform CAN Bus Voltage Test: With key ON, measure voltage of CAN High (2.5V - 2.7V) and CAN Low (2.3V - 2.5V) to ground.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery cable to prevent electrical spikes during testing.

2. 2

   Isolate the Fault

   Based on the results of the resistance and voltage tests, trace the CAN A (Vehicle CAN) wiring harness from the ECM to the rest of the vehicle network.

3. 3

   Repair Wiring

   If a short or open circuit is found in the harness, repair the wiring using OEM-approved splicing methods, or replace the affected harness section entirely.

4. 4

   Clean Connectors

   Disconnect the ECM harness connectors. Clean the pins with electrical contact cleaner and apply dielectric grease to prevent moisture ingress. Reconnect them securely.

5. 5

   Replace Terminating Resistors

   If the resistance test showed 120 ohms and the wiring is intact, locate and replace the faulty CAN terminating resistor on the network.

6. 6

   Clear Codes

   Reconnect the battery, turn the ignition ON, and use the CNH Electronic Service Tool (EST) or an equivalent diagnostic scanner to clear the ENG 3096 fault code.

7. 7

   Test Drive

   Run the machine and verify that the ECM successfully communicates with the vehicle network (e.g., the instrument cluster displays engine RPM and temperature correctly) and the code does not return. Note: If the wiring and resistors test perfectly but the code persists, the ECM's internal CAN transceiver has failed, and the ECM must be replaced.