Case IH 19341 – Engine Control Unit (ECU): Timeout error of CAN receive frame heater control unit (HCU) Data

The Engine Control Unit (ECU) has lost Controller Area Network (CAN) bus communication with the Heater Control Unit (HCU), or the HCU is failing to send its diagnostic, current, and voltage data within the expected timeframe.

• Tier 4b
• Case IH T7 Series (Tier 4B)
• Case IH Farmall Series (90C, 100C, 110C, 110U)
• Case IH Magnum
• Case IH Maxxum
• Case IH Puma
• Case IH Steiger

1. 1

   Verify the power supply and ground to the HCU. Inspect the Heater Control Unit Supply (Terminal 30), Ground (Terminal 31), and Activation (Terminal 87) circuits for blown fuses or voltage drops.

2. 2

   Check the CAN bus wiring (HCU Can Lo and HCU Can Hi) between the HCU and the ECU for continuity, shorts to ground, or open circuits.

3. 3

   Inspect the HCU wiring harness connector for corrosion, moisture ingress, or pushed-out pins.

4. 4

   Inspect the DEF tank heater control valve and hoses. Look for a sticking valve or incorrectly installed hoses that could cause hot water to circulate continuously and overheat the DEF tank.

5. 5

   Connect a Case IH Electronic Service Tool (EST) to monitor controller status, verify if the HCU is visible on the CAN network, and check for secondary DEF system codes.

1. 1

   Disconnect Power

   Turn off the battery isolator switch to ensure safety before working on the electrical system.

2. 2

   Harness Repair

   If the diagnostic checks reveal a broken wire or short in the CAN Hi/Lo lines or the power/ground circuits, repair the wiring harness and replace any damaged connector pins.

3. 3

   Replace the HCU

   If the wiring, power, and ground are all intact but the CAN timeout persists, the Heater Control Unit has failed internally and must be replaced.

4. 4

   Address Valve/Hose Routing

   If the DEF heater control valve is damaged due to overheating, replace the valve. Ensure the DEF heater lines are routed correctly. (Note: On tractors built in Fargo, the DEF heater line with the 'red' band must be connected to the top tube running to the front part of the engine head to prevent continuous hot water circulation).

5. 5

   Clear Codes

   Reconnect the battery, turn the ignition on, and use the EST to clear fault code 19341. Verify that CAN communication with the HCU has been restored and the code does not return.