Case IH 19827 – Engine Control Module (ECM) / Vehicle Control Module (VCM): Upstream oxidation catalyst temperature is too high

The temperature sensor located just before (upstream of) the Diesel Oxidation Catalyst (DOC) in the exhaust aftertreatment system is detecting exhaust gas temperatures that exceed the maximum safe operating threshold.

• Tier 4b
• 580N
• 580SN
• 580SN WT
• 590SN
• TR270
• TR310
• TR340
• TV370
• TV450

1. 1

   Connect your diagnostic tool (e.g., PT-Box Tool or Case EST) to verify if the fault is currently present and active.

2. 2

   Check for related sensor codes, such as 3686 (DOC upstream temperature sensor signal drift at cold start) or codes indicating voltage issues (e.g., 19066 Upstream oxidation catalyst temperature sensor voltage is higher than expected).

3. 3

   Inspect the upstream DOC temperature sensor to ensure it is actually installed, correctly mounted, and securely tightened in the exhaust piping.

4. 4

   Inspect the sensor's wiring harness and connectors for physical damage, melting, open circuits, or shorts to ground/battery.

1. 1

   Power Down

   Turn off the machine and disconnect the battery ground if repairing wiring. Allow the exhaust system and DOC to cool completely to avoid severe burns.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a short or break in the wiring harness leading to the sensor, repair or replace the affected harness section.

3. 3

   Remove the Sensor

   If the wiring is intact but the sensor is internally faulty or reading out of range, disconnect the sensor's electrical connector. Use a wrench to carefully unthread the upstream oxidation catalyst temperature sensor from the DOC housing/exhaust pipe.

4. 4

   Install the New Sensor

   Thread the new temperature sensor into the exhaust bung. Tighten to the manufacturer's specified torque to ensure an exhaust-tight seal without damaging the threads.

5. 5

   Reconnect

   Plug the sensor back into the engine wiring harness.

6. 6

   Clear and Test

   Reconnect the battery, connect the diagnostic tool, clear the inactive 19827 fault code, and run the engine. Monitor the live DOC upstream temperature data to ensure it is reading within normal parameters and the code does not return.