Case IH 19278 – Engine Control Unit (ECU) / Vehicle Control Module (VCM): Timeout of CAN frame of Intermediate gas temperature and pressure message AT1MGTO

This is a Controller Area Network (CAN) communication error. The Engine Control Unit (ECU) or Vehicle Control Module (VCM) expects to receive a specific data message (designated as "AT1MGTO") from the intermediate gas temperature and pressure sensor located in the exhaust aftertreatment system. A "timeout" means the ECU did not receive this data packet within the programmed time window, indicating that the sensor has stopped broadcasting, the CAN bus wiring is compromised, or the sensor's internal module has failed.

• Tier 4b
• Case N-Series Loader Backhoes (580N, 590N)
• Case IH Tractors (Farmall 100C, 105A, 110A, 115U, Maxxum, Puma)

1. 1

   Check for accompanying codes: Look for other CAN timeout codes (such as 19269 or 19277). If multiple CAN timeout codes are present, the issue is likely a main CAN bus wiring failure rather than a single sensor.

2. 2

   Wiring harness inspection: Visually inspect the CAN wiring harness running from the exhaust aftertreatment sensors to the ECU. Look for chafing, melted wires from exhaust heat, or breaks.

3. 3

   Connector check: Disconnect the intermediate gas temperature/pressure sensor. Inspect the pins for corrosion, moisture ingress, or pushed-out terminals.

4. 4

   Power and ground: Verify that the sensor is receiving proper voltage and ground. A CAN sensor cannot broadcast its message if it has lost power.

1. 1

   Preparation

   Turn off the machine, remove the key, and disconnect the negative battery cable to prevent electrical shorts. Ensure the exhaust system has completely cooled down.

2. 2

   Locate the Sensor

   Locate the intermediate gas temperature and pressure sensor on the exhaust aftertreatment assembly (typically positioned between the Diesel Oxidation Catalyst [DOC] and the Diesel Particulate Filter [DPF]).

3. 3

   Disconnect

   Unplug the electrical connector from the sensor harness.

4. 4

   Removal

   Using the appropriate wrench, carefully unscrew the sensor from the exhaust pipe. Note: Exhaust sensors frequently seize due to extreme heat cycles. Apply penetrating oil to the threads and allow it to soak if the sensor is stuck.

5. 5

   Installation

   Apply a small amount of high-temperature anti-seize compound to the threads of the new sensor (if not already pre-applied by the manufacturer). Thread the sensor in by hand to prevent cross-threading, then tighten to OEM torque specifications.

6. 6

   Reconnect

   Plug the electrical connector back into the machine's harness, ensuring the locking tab clicks into place.

7. 7

   Clear Codes

   Reconnect the battery. Use a diagnostic scan tool to clear the 19278 fault code from the ECU.

8. 8

   Validation

   Start the engine and allow it to reach operating temperature. You may need to perform a stationary/forced DPF regeneration to verify the sensor is reading correctly and the code does not return.