Case IH t22 – ECM: Boost Air Temperature Sensor, Grounded Or Current Above Normal Range

The Engine Control Module (ECM) has detected that the boost air temperature sensor signal is outside of its normal operating parameters, specifically indicating a short to ground or a current/voltage spike. This indicates an issue with the sensor measuring the temperature of the pressurized intake air after the intercooler. The condition is typically caused by an internal short circuit within the sensor, a rubbed or pinched wiring harness shorting to the chassis, or severe corrosion in the connector.

• MXM
• MXM Series
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• TM Series
• TM115-TM190

1. 1

   Visually inspect the Boost Air Temperature Sensor and wiring harness for chafing, melted insulation, or pinched wires that could cause a ground short.

2. 2

   Disconnect the sensor and inspect the connector pins for water intrusion, bent pins, or corrosion.

3. 3

   Perform a resistance test on the sensor using a multimeter. A healthy sensor reads ~322 ohms at 80 degrees C or ~2.3 - 2.9 kOhms at 20 degrees C. 0 ohms or open indicates internal failure.

4. 4

   With the key ON and engine off, test the harness reference voltage wire from the ECM to ensure it is not grounded to the chassis.

1. 1

   Preparation

   Park the tractor on a level surface, apply the parking brake, turn off the ignition, and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Removal

   Disconnect the electrical harness connector from the Boost Air Temperature Sensor.

3. 3

   Extraction

   Using a deep socket or wrench, carefully unscrew the faulty sensor from the intake manifold or boost pipe.

4. 4

   Installation

   Thread the new sensor into the port by hand to prevent cross-threading. Ensure the new O-ring or sealing washer is in place. Tighten the sensor to the manufacturer's specified torque (typically around 15 N·m for intake sensors).

5. 5

   Reconnection

   Plug the electrical connector back into the sensor until the locking tab clicks.

6. 6

   Clear Codes

   Reconnect the battery. Turn the ignition key to the ON position. Use the tractor's H-Menu (diagnostic menu) or an OBD/diagnostic scan tool to clear the inactive t22 fault code.

7. 7

   Verification

   Start the engine and verify that the fault code does not return and that the tractor operates without derating.