New Holland NH 3096 – Engine Control Module (ECM / ECU): CAN (A) Hardware - NO SIGNAL / Primary Vehicle CAN Bus Failure - Bus Off On CAN Node A

The Engine Control Module (ECM) has lost communication on the primary vehicle CAN Bus A. The ECM's internal CAN controller has detected too many transmit/receive errors and has forced itself into a 'Bus Off' state to prevent disrupting the rest of the network.

• T5
• T6
• T7
• T8
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• Excavators

1. 1

   Verify if the code is active or inactive. If inactive, it may be a normal shutdown timing discrepancy between the ECU and XCM. Clear the code and see if it returns.

2. 2

   Confirm stable battery voltage and inspect main chassis/engine grounds, as low voltage or bad grounds cause CAN modules to drop offline.

3. 3

   Visually inspect CAN bus wiring looms at common movement or pinch points (e.g., seat area, steering column, cab pivot, loader brackets) for chafing.

4. 4

   Inspect the ECM and XCM connectors for moisture, corrosion, or backed-out pins.

5. 5

   Perform a CAN Bus resistance test with the battery disconnected by measuring resistance between CAN High (Yellow) and CAN Low (Green) at the diagnostic port. 60 ohms is healthy, 120 ohms indicates a broken wire or failed terminating resistor, and 0 ohms indicates a short circuit.

1. 1

   Disconnect Power

   Disconnect the negative battery terminal before performing any electrical repairs.

2. 2

   Isolate the Fault

   If the resistance test yielded 120 ohms or 0 ohms, begin unplugging modules on CAN Bus A one by one. If the resistance returns to 60 ohms after unplugging a specific module, the fault lies within that module or its immediate pigtail.

3. 3

   Repair Wiring

   If a break or short is found in the harness, repair the wires. Maintain the wire twist (approximately one twist per inch), use proper solder/crimp connectors, and ensure wire lengths are not significantly altered from the original, as this affects network performance.

4. 4

   Address Moisture/Corrosion

   If connectors are wet or corroded, clean them thoroughly with contact cleaner, dry them, and apply dielectric grease before reconnecting.

5. 5

   Replace Terminating Resistor

   If the wiring is intact but the circuit reads 120 ohms, locate and replace the failed 120-ohm terminating resistor at the end of the CAN A network.

6. 6

   Clear Codes and Test

   Reconnect the battery. Use the New Holland Electronic Service Tool (EST) or the onboard diagnostic display to clear the fault codes. Run the machine to verify the code does not return.