New Holland UCM 9151 – UCM (Universal Control Module): CAN Bus Communication: Timed out after 5 seconds ("Bus-Off at CAN-Bus No.1")

This is a network communication error indicating that the control module has lost communication with the vehicle's primary controller area network (CAN-Bus No.1) for a duration exceeding 5 seconds. When the error counter exceeds its limit, the module enters a "Bus-Off" state, actively removing itself from participating in CAN traffic to prevent network corruption.

• L213
• L216
• L218
• L220
• L221
• L223
• L225
• L230
• L318
• L320
• L323
• L325
• L328
• L330
• L334
• C227
• C232
• C238
• C327
• C332
• C334
• C337
• C345

1. 1

   Verify battery voltage and ensure the UCM is receiving proper unswitched and switched power.

2. 2

   Disconnect the UCM harness and inspect the pins for corrosion, moisture, or pushed-back/bent pins.

3. 3

   With the battery disconnected, measure resistance across CAN High and CAN Low pins on the diagnostic connector (should read approximately 60 ohms).

4. 4

   Check the CAN-Bus No.1 wiring harness for continuity, shorts to ground, or shorts to battery voltage.

5. 5

   Use the New Holland Electronic Service Tool (EST) to clear fault codes and operate the machine to see if the code returns.

1. 1

   Prepare machine for repair

   Turn off the machine, engage the parking brake, and disconnect the negative battery cable.

2. 2

   Repair wiring harness

   If the diagnostic checks revealed a wiring issue (short or open circuit) on CAN-Bus No.1, locate the chafed or broken wire in the main chassis harness and repair it using approved environmental splices.

3. 3

   Clean connectors

   If the connectors are corroded, clean them thoroughly with electrical contact cleaner and apply dielectric grease before reconnecting.

4. 4

   Restore power

   Reconnect the battery and turn the key to the ON position.

5. 5

   Diagnose UCM failure

   If the wiring and power supplies are verified to be in good condition but the UCM still reports a "Bus-Off" state, the UCM has suffered an internal hardware/transceiver failure and must be replaced.

6. 6

   Replace UCM

   Install the new UCM.

7. 7

   Flash new UCM

   Connect the New Holland EST. A new UCM will not operate the machine out of the box; it must be flashed with the correct machine dataset/software to restore self-learning parameters and CAN communication.