Case IH t1 – Electronic Engine Controller (ECU) or PTO/Hand Throttle Controller (XCM): Foot Throttle Position Sensor, Grounded Or Current Above Normal Range

The control module is receiving a signal from the foot throttle potentiometer that is either shorted directly to ground or is drawing an electrical current that exceeds the normal operating parameters.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• Farmall 70A
• Farmall 95U
• Farmall 105U
• Farmall 115U
• Puma
• Magnum

1. 1

   Inspect the wiring harness running from the foot throttle position sensor to the ECU/XCM for pinched wires, chafed insulation, or exposed copper shorting to the chassis.

2. 2

   Disconnect the sensor and inspect the pins for corrosion, moisture, or bent terminals.

3. 3

   Perform a circuit test: with the sensor disconnected, turn the key to the 'ON' position. If the code changes from t1 to t2, the wiring harness is likely intact and the sensor has failed internally.

4. 4

   Verify that the sensor supply voltage from the ECU is within specification (typically 5V or 8V) and not shorted to a higher voltage source.

1. 1

   Preparation

   Park the tractor on level ground, apply the parking brake, and turn off the engine.

2. 2

   Access the Sensor

   Locate the foot throttle position sensor potentiometer, which is mechanically linked to the foot pedal assembly in the cab.

3. 3

   Harness Repair

   If the diagnostic checks revealed a short to ground in the wiring harness, splice and repair the damaged wire using heat-shrink connectors, then re-loom the harness.

4. 4

   Sensor Replacement

   If the sensor is internally shorted, remove the mounting hardware securing the potentiometer to the pedal assembly. Install the new OEM sensor and tighten the hardware.

5. 5

   Reconnect

   Plug the electrical harness back into the new sensor.

6. 6

   Calibration

   Perform a calibration procedure. This can be a Quick Relearn (disconnecting and reconnecting the potentiometer with the key switch ON) or an H-Menu Calibration to calibrate the new minimum and maximum voltage sweeps of the pedal.

7. 7

   Clear Codes

   Cycle the key, clear the stored fault codes, and test the foot throttle to ensure smooth engine RPM response.