New Holland IC 9406 – Instrument Cluster (IC): CAN Time Out - Loss of all communication from UCM

The Controller Area Network (CAN) bus has stopped receiving data messages from the Universal Control Module (UCM).

• L213
• L215
• L218
• L220
• L221
• L223
• L225
• L230
• C227
• C232
• C238
• SR130
• SR160
• SR175
• SV185

1. 1

   Check the UCM relay (often labeled as the EH control relay, K003, or VCM relay) and the Main Power relay by using a fused jumper wire between pins 30 and 87 (sometimes labeled pins 1 and 4) to see if communication is restored.

2. 2

   Inspect the wiring harness located on the left side of the machine, under the cab, specifically checking the 4 diodes spliced into this harness on pigtails for corrosion.

3. 3

   Check all fuses in the main fuse box for blown circuits.

4. 4

   Verify the continuity of the CAN bus wires between the Instrument Cluster and the UCM.

1. 1

   Safety First

   Turn off the machine, lower the boom (or engage the boom lock), and disconnect the negative battery cable.

2. 2

   Inspect Relays & Fuses

   Open the fuse box and test the Main Power and UCM relays. Replace any that click weakly or fail a continuity test.

3. 3

   Inspect the Left-Side Harness

   Lift the cab to access the chassis wiring harness on the left side. Locate the 4 inline diodes.

4. 4

   Repair Diodes

   If the diodes are corroded, cut them out and solder/heat-shrink new equivalent diodes into the harness. (For temporary diagnostic purposes, you can jump the wires together to see if the UCM powers up and the code clears).

5. 5

   Clean Connectors

   Unplug the connectors at the UCM and the Instrument Cluster. Inspect for backed-out pins, moisture, or corrosion. Clean with electrical contact cleaner and apply dielectric grease before reconnecting.

6. 6

   Software Update

   If the wiring is perfectly intact, note that New Holland issued Service Bulletin 2014-021 (NHC L SB) regarding software improvements for the Instrument Cluster (IC) and UCM to resolve various electro-hydraulic communication issues. A dealer may need to flash the modules with updated software.