Case IH t58 – Transmission/EDC Controller: Crankshaft Speed Sensor, Data Incorrect

The control module is receiving an erratic, implausible, or invalid signal from the crankshaft speed sensor. This sensor is critical for engine timing and transmission calibration.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• TM115
• TM190

1. 1

   Check for Short Circuits: Look for code t59 (shorted to low source) or t5A (shorted to high source). If present, inspect the wiring harness for chafing or exposed wires grounding out.

2. 2

   Check for Polarity Issues: Look for code t5B or t5C (Reverse polarity of engine speed sensor). This usually indicates a wiring repair was done incorrectly or pins are swapped in the connector.

3. 3

   Physical Inspection: Inspect the sensor connector for corrosion, moisture, or loose pins. Remove the sensor and check the magnetic tip for excessive metallic debris, which can distort the signal data.

1. 1

   Power Down

   Turn off the key switch, place all shift levers in neutral, block the wheels, and disconnect the battery.

2. 2

   Locate and Remove

   Locate the crankshaft speed sensor on the engine block near the flywheel housing. Disconnect the electrical harness.

3. 3

   Extract Sensor

   Remove the M6 retaining screw (Hex socket head) and carefully pull the sensor out of its bore.

4. 4

   Install New Part

   Insert the replacement sensor, ensuring it seats flush. Secure it with the retaining screw. Reconnect the electrical harness.

5. 5

   Clear Codes & Calibrate

   Reconnect the battery and start the engine. Enter calibration mode (holding High and Low range buttons while starting the engine until 'CAL' appears). Set engine speed to exactly 1200 ERPM (±100) and proceed through the clutch calibration steps until 'END' is displayed.