Case IH t5A – Engine Control Unit (ECU) or Tractor Control Unit (TCU) / Transmission Controller: Crankshaft Speed Sensor, Shorted To High Source

The control unit is receiving a sensor feedback voltage that is higher than the normal operating threshold (typically greater than 4.5 Volts). This indicates that the sensor's signal circuit is shorted to a power source, either internally within the sensor or externally in the wiring harness.

• MXM
• MXM Series
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• Magnum
• Maxxum
• Puma
• Steiger

1. 1

   Check the Error Log: Save the error log, erase it, and restart the ECU. If the fault returns during the next driving cycle, it is an active hard fault.

2. 2

   Inspect Connectors: Check the sensor's 3-pin electrical plug connector and the main Tractor Control Unit (TCU) / ECU connectors. Ensure they are fully connected, not damaged, and that the pins are tight and in the correct position.

3. 3

   Test the Harness: Inspect the wiring harness between the sensor and the controller for chafing, melting, or pinched wires that could cause the signal wire to short against a 5V reference or 12V battery source.

1. 1

   Locate the Sensor

   Find the crankshaft speed sensor, which is positioned directly near the engine flywheel casing or the primary timing gear housing.

2. 2

   Disconnect Power

   Turn off the machine and disconnect the battery to protect the ECU.

3. 3

   Disconnect and Remove

   Unplug the 3-pin sealed electrical connector from the sensor. Remove the mounting hardware and extract the sensor from the casing.

4. 4

   Repair Wiring (If Applicable)

   If your diagnostic checks revealed a short in the wiring harness, repair or replace the damaged section of the harness.

5. 5

   Install New Sensor

   If the wiring is intact, the sensor itself has failed internally. Install the new OEM crankshaft speed sensor into the mounting slot and secure it.

6. 6

   Reconnect

   Plug the 3-pin connector back in, ensuring the weather seal is tight to shut out field soil and dust.

7. 7

   Clear Codes and Calibrate

   Reconnect the battery, turn the key switch on, and use an Electronic Service Tool (or the tractor's H-Menu) to clear the fault codes. Note: Depending on the model, replacing a sensor or resetting the non-volatile memory may require you to perform a Transmission/EDC calibration setup procedure.