Case IH 19340 – Engine Control Unit (ECU): Timeout error of CAN receive frame heater control unit (HCU) Data

The Heater Control Unit (HCU) is responsible for controlling and monitoring the line heaters for the Diesel Exhaust Fluid (DEF) / AdBlue hoses. Code 19340 is triggered when the expected CAN data frames from the HCU stop arriving (time out), indicating a loss of communication between the HCU and the rest of the network.

• Tier 4b
• Case IH Puma
• Case IH Optum
• Case IH Vestrum
• Case IH Farmall
• Case IH 580SN Backhoe Loader

1. 1

   Inspect the dedicated fuses and relays for the HCU (40A fuse and HCU relay) to ensure the HCU can power on.

2. 2

   Inspect the wiring harness connecting the HCU to the ECU for physical damage, corrosion at the connectors, or broken wires.

3. 3

   Verify the integrity of the CAN Hi and CAN Lo lines at the HCU connector for proper voltage and continuity back to the ECU.

4. 4

   Ensure the HCU has a solid block ground connection.

1. 1

   Turn off the machine and disconnect the battery to prevent electrical shorts.

   Turn off the machine and disconnect the battery to prevent electrical shorts.

2. 2

   Locate the main fuse/relay panel and test the 40A HCU fuse and the HCU relay. Replace them if they are blown or faulty.

   Locate the main fuse/relay panel and test the 40A HCU fuse and the HCU relay. Replace them if they are blown or faulty.

3. 3

   If the fuses are intact, locate the DEF Heater Control Unit (HCU) on the machine.

   If the fuses are intact, locate the DEF Heater Control Unit (HCU) on the machine.

4. 4

   Disconnect the HCU harness and inspect the pins for corrosion or pushed-out terminals. Clean with electrical contact cleaner and reconnect securely.

   Disconnect the HCU harness and inspect the pins for corrosion or pushed-out terminals. Clean with electrical contact cleaner and reconnect securely.

5. 5

   If power, ground, and CAN continuity are all verified as good but the ECU still reports a timeout (Code 19340), the internal CAN transceiver of the HCU has likely failed.

   If power, ground, and CAN continuity are all verified as good but the ECU still reports a timeout (Code 19340), the internal CAN transceiver of the HCU has likely failed.

6. 6

   Unbolt the faulty HCU, install the replacement unit, and reconnect the wiring harness.

   Unbolt the faulty HCU, install the replacement unit, and reconnect the wiring harness.

7. 7

   Reconnect the battery, turn the ignition on, and use a CNH Electronic Service Tool (EST) to clear the inactive fault codes and verify that CAN communication has been restored.

   Reconnect the battery, turn the ignition on, and use a CNH Electronic Service Tool (EST) to clear the inactive fault codes and verify that CAN communication has been restored.