Case IH 19604 – DCU: CAN receive frame ET1 (Oil and Water temp engine) | SAE J1939 Check for CAN receive signal : (Oil temperature not in range) | P0600 Serial Communication Link.

The DCU (Dosing Control Unit) is receiving an invalid or out-of-range engine oil temperature signal over the SAE J1939 CAN bus (specifically on data frame ET1) from the Engine Control Module (ECM). The expected data packet is either corrupted, missing, or reporting an impossible temperature value.

• Tier 4a
• Case IH Magnum Tractors: 235, 260, 290, 315, 340 (Series 4)
• Case IH Steiger / Quadtrac Tractors: 350, 400, 450, 500, 550, 600
• Case IH Puma Tractors
• Case IH Combines: 5140, 6140, 7140, 7240, 8240, 9240

1. 1

   Check for accompanying DCU CAN codes (e.g., 19605, 19606, or 19607). Multiple CAN codes indicate a broken CAN bus wire or failed terminating resistor rather than a bad sensor.

2. 2

   Verify Engine Oil Temperature data using the Case IH Electronic Service Tool (EST). If the ECM reads correctly but the DCU logs 19604, the fault is in the CAN bus communication. If the ECM reads an erratic or default temperature, the fault is with the physical sensor or its wiring.

3. 3

   Perform a CAN bus resistance test across the J1939 CAN bus pins with the battery disconnected. It should read approximately 60 ohms; a reading of 120 ohms indicates a broken terminating resistor or CAN wire.

1. 1

   Disconnect battery

   Disconnect the machine's battery power.

2. 2

   Locate sensor

   Locate the Engine Oil Temperature Sensor (often a combined oil temp/pressure sensor on FPT engines) on the engine block.

3. 3

   Inspect sensor connector

   Disconnect the sensor harness and inspect the connector pins for corrosion, pushed-back pins, or moisture intrusion.

4. 4

   Test sensor resistance

   Test the sensor's resistance with a multimeter against OEM specifications. If it is open or shorted, replace the sensor.

5. 5

   Test wiring continuity

   If the sensor tests good, perform a continuity test on the signal and ground wires between the sensor connector and the Engine ECM. Repair any chafed or broken wires.

6. 6

   Inspect CAN bus harness

   If the CAN bus is at fault, inspect the main CAN bus harness connecting the Engine ECM to the DCU.

7. 7

   Check harness routing

   Pay special attention to bulkhead connectors and areas where the harness routes near the engine block or articulation joints (on Steiger models), as vibration often causes wire chafing.

8. 8

   Clean connectors

   Clean the connectors with contact cleaner and ensure tight pin fitment.

9. 9

   Clear fault codes

   Reconnect all components, restore battery power, and use the EST to clear the fault codes.

10. 10

    Verify repair

    Run the engine and monitor the DCU data to ensure the ET1 frame is being received and the oil temperature is in range.