Case IH 19802 – DCU (Dosing Control Unit): UREA Tank Temperature not plausible with Pump module temperature - Temp over CAN: SAE J1939 Timeout Temp sensor connected directly: SRC high - P0600 Serial Communication Link

This code indicates a plausibility error and communication failure regarding the Diesel Exhaust Fluid (DEF/Urea) temperature. The control module is receiving inaccurate or unreliable temperature data from the urea tank when compared to the temperature reading at the DEF pumping unit. Specifically, the system has detected a timeout on the SAE J1939 CAN bus, or the directly connected temperature sensor is reading 'SRC high' (Source High), which typically points to an open circuit, a short, or a failed sensor.

• Tier 4a
• Case IH Steiger / Rowtrac 350
• Case IH Steiger / Rowtrac 400
• Case IH Steiger / Rowtrac 450
• Case IH Steiger / Rowtrac 500
• Case IH Steiger / Rowtrac 550
• Case IH Steiger / Rowtrac 600
• Case IH Magnum 275
• Case IH Magnum MX210
• Case IH Magnum MX230
• Case IH Magnum MX255
• Case IH Magnum MX285
• Case IH Puma 125
• Case IH Puma 165
• Case IH Puma 210

1. 1

   Check for related active DCU codes that specify the exact electrical failure, such as 19804 (Open Circuit), 19805 (Short to Battery/High), or 19806 (Short to Ground/Low).

2. 2

   Inspect the SAE J1939 CAN bus wiring between the DEF tank temperature sensor, the DEF pump module, and the DCU for chafed wires, pinched harnesses, or broken lines.

3. 3

   Disconnect the DEF tank temperature sensor and inspect the pins for corrosion, moisture intrusion, or loose terminals.

4. 4

   Perform a sensor plausibility test using the Electronic Service Tool (EST) to monitor the live temperature data of the DEF tank versus the DEF pump module. If the tank sensor reads an impossible value while the pump module reads ambient, the sensor has drifted or failed.

1. 1

   Power Down

   Turn off the machine and disconnect the battery to prevent electrical spikes during repair.

2. 2

   Repair Wiring (If Applicable)

   If the diagnostic checks revealed a broken wire or corroded connector on the CAN bus or sensor pigtail, repair the wiring harness or replace the damaged connector terminal.

3. 3

   Replace the Sensor

   If the wiring is intact and the sensor is confirmed faulty (SRC high / open circuit), the DEF tank temperature sensor must be replaced. Note: On many Case IH Tier 4 systems, the temperature sensor is integrated into the DEF tank level sender unit (often referred to as the WEMA tank unit or suction tube assembly).

4. 4

   Reassemble and Reconnect

   Install the new sensor/sender unit into the DEF tank and securely reconnect the electrical harness.

5. 5

   Clear Codes

   Reconnect the battery. Connect the Electronic Service Tool (EST) to clear the inactive 19802 fault code from the DCU.

6. 6

   Verify Operation

   Turn the key on and verify that the DEF tank temperature is now reading a plausible value matching ambient/pump module temperatures. Run the machine to ensure the code does not return.