Case IH 19815 – Engine Control Module (ECM) / Engine ECU: Diagnostic fault check for charged air cooler downstream temperature sensor

This code indicates that the Engine Control Module (ECM) has detected an implausible signal, out-of-range value, or failed internal diagnostic check from the temperature sensor located downstream of the charged air cooler (intercooler).

• Tier 4b
• MX Magnum
• Steiger
• Puma series
• T7 Series Tier 4B
• 521N
• 621N

1. 1

   Inspect the wiring harness and connectors leading to the charged air cooler downstream temperature sensor for chafed wires, melted insulation, loose pins, moisture, dirt, or corrosion.

2. 2

   Remove the sensor and inspect the probe for heavy soot, carbon buildup, or oil contamination from the turbocharger that could insulate the sensor.

3. 3

   Use a multimeter to check the sensor's resistance and verify it matches the OEM specification for the ambient temperature. Check for a proper 5V reference signal and ground from the ECM at the harness connector.

4. 4

   Inspect the charge air cooler (intercooler) and all downstream intake piping/boots for cracks, loose clamps, or leaks that could cause temperature readings to fall outside expected parameters.

1. 1

   Preparation

   Turn off the engine, remove the key, and disconnect the negative battery cable to prevent electrical shorts.

2. 2

   Locate the Sensor

   Locate the charged air cooler downstream temperature sensor. It is typically threaded into the intake piping just after the charge air cooler outlet or directly on the intake manifold.

3. 3

   Removal

   Depress the locking tab and disconnect the electrical pigtail from the sensor. Using an appropriately sized deep socket or wrench, carefully unthread the sensor from the intake pipe/manifold.

4. 4

   Installation

   Thread the new sensor into the port by hand to prevent cross-threading. Tighten the sensor to the OEM torque specification (do not overtighten, as the brass/plastic threads can break).

5. 5

   Reassembly

   Reconnect the electrical harness until it clicks into place. Reconnect the negative battery cable.

6. 6

   Verification

   Connect a diagnostic scan tool, clear the inactive 19815 fault code, and run the engine to operating temperature to ensure the code does not return.