Case IH 19342 – Engine Control Module (ECM): Timeout error of CAN receive frame HCUData

A Controller Area Network (CAN) communication failure indicating the main engine controller is expecting to receive a regular data broadcast (the HCUData frame) from the Heater Control Unit (HCU), but the message is timing out.

• Tier 4b
• Puma
• Magnum
• Steiger
• Optum
• Maxxum
• N-Series Loader Backhoes
• 580N
• 590SN
• Wheel loaders

1. 1

   Check power and ground to the HCU to verify proper battery voltage and a clean ground. Look for a blown fuse or bad relay supplying the DEF heating system.

2. 2

   Inspect the HCU harness connectors for corrosion, moisture intrusion, or pushed-out pins.

3. 3

   Test the CAN Bus wiring by measuring resistance across the CAN High and CAN Low pins at the HCU connector with the battery disconnected (should read approximately 60 ohms).

4. 4

   Check the CAN lines between the HCU and the ECM for open circuits, short-to-ground, or short-to-voltage.

5. 5

   Check for accompanying codes to determine if multiple modules are reporting CAN timeout errors, indicating the entire CAN network may be compromised rather than just the HCU.

1. 1

   Power Down

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

2. 2

   Locate the HCU

   Locate the Heater Control Unit, which is typically mounted near the DEF supply module or DEF tank.

3. 3

   Perform Wiring Repairs

   If the diagnostic checks revealed a broken CAN wire or a short circuit in the harness, repair the damaged section of the wiring harness.

4. 4

   Replace the HCU

   If power, ground, and CAN continuity are all verified as good, the CAN controller inside the HCU has failed internally. Remove the mounting bolts and disconnect the electrical harness to remove the defective HCU.

5. 5

   Install the New HCU

   Mount the replacement Heater Control Unit and securely click the harness connector into place.

6. 6

   Clear Codes and Test

   Reconnect the battery. Connect the CNH Electronic Service Tool (EST), clear the inactive 19342 fault code, and cycle the key. Monitor the CAN network to ensure the HCU is actively communicating and the DEF heating system is functional.