Case IH t24 – Electronic Management Unit (EMU) / Engine ECU: Boost Air Temperature Sensor, Shorted To Low Source

The control module is receiving a voltage signal from the boost air temperature sensor that is below the minimum acceptable threshold, indicating the signal wire is shorted directly to ground.

• MXM
• Case IH MXM 120
• Case IH MXM 130
• Case IH MXM 140
• Case IH MXM 155
• Case IH MXM 175
• Case IH MXM 190

1. 1

   Inspect the wiring harness leading to the Boost Air Temperature Sensor for rubbed-through insulation, pinched wires, or melted conduit.

2. 2

   Unplug the connector from the Boost Air Temperature Sensor and check if the fault code changes to 'Open Circuit' (t23) to determine if the sensor is internally shorted.

3. 3

   If the code remains t24 with the sensor unplugged, use a digital multimeter to test the signal wire for continuity to ground.

4. 4

   Verify that the sensor is receiving the correct 5V reference voltage from the ECU at the connector.

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Wiring Repair

   If the harness tested bad, trace the signal wire back to the EMU. Locate the short to ground, splice in a new section of wire using weather-sealed heat shrink connectors, and re-loom the harness.

3. 3

   Sensor Replacement

   Locate the Boost Air Temperature Sensor on the intake/boost piping. Disconnect the electrical harness, unthread the faulty sensor from the manifold, thread the new sensor into place and tighten to OEM torque specs, and reconnect the electrical harness.

4. 4

   Clear Codes & Calibrate

   Reconnect the battery and turn the key ON to move the code to an inactive state, then clear the inactive codes. If the non-volatile memory was reset or major electrical repairs were done, perform an EDC/Transmission calibration via the H-Menu.