Case IH t31 – Engine Control Unit (EDC / Engine ECU): Boost air pressure sensor, grounded or current above normal range

The control module is detecting an electrical short to ground or an abnormally high current draw on the circuit belonging to the boost air pressure (MAP) sensor, which monitors the intake manifold pressure.

• MXM
• Case IH MXM Series
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• Case IH MXU Series
• MXU 110
• MXU 115
• MXU 125
• MXU 135
• Case IH Puma Series
• TM120
• TM130
• TM140
• TM155
• TM175
• TM190
• TS-A series

1. 1

   Inspect the wiring harness leading to the boost air pressure sensor for chafing, melted insulation, or exposed wires that could be shorting to the engine block (ground).

2. 2

   Disconnect the sensor and check the 4-terminal connector for corrosion, moisture, or bent pins.

3. 3

   Test the resistance at the sensor terminals (at 20 °C) between specific terminals (e.g., between terminals 3 and 4, and 3 and 1) to see if the sensor has failed internally.

4. 4

   With the key ON and sensor disconnected, verify that the sensor is receiving the correct 5V reference voltage and that the ground circuit is intact.

1. 1

   Power Down

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

2. 2

   Locate the Sensor

   Locate the boost air pressure sensor, which is mounted directly on the intake manifold (suction pipe) of the engine.

3. 3

   Remove the Sensor

   Disconnect the 4-terminal wiring harness from the sensor. Remove the two mounting bolts securing the sensor to the manifold.

4. 4

   Install the New Sensor

   Clean the mating surface on the intake manifold. Insert the new sensor and secure it with the two bolts.

5. 5

   Reconnect

   Plug the wiring harness back into the sensor, ensuring the locking tab clicks into place. Reconnect the battery.

6. 6

   Clear Codes

   Turn the key to the ON position. You may need to access the tractor's H-Menu (diagnostic menu) via the instrument cluster to clear the stored t31 fault code and verify that it changes from an "active" to an "inactive" state.