Case IH 4 – Electronic Hitch Control Module (CFPS or GCM1) or Transmission Control Module (TCM): Wheel speed greater than maximum speed of tractor.

This code is triggered when the wheel speed sensor (transmission output speed sensor) reports a speed value that exceeds the tractor's maximum programmed ground speed, or when there is a severe mismatch between the wheel speed sensor and the performance monitor radar (ground speed radar).

• MXM
• MXM120
• MXM130
• MXM140
• MXM155
• MXM175
• MXM190
• Puma 115
• Puma 125
• Puma 140
• Puma 155
• Puma 165
• Puma 180
• Puma 195
• Puma 210
• Maxxum 100
• Maxxum 110
• Maxxum 115
• Maxxum 120
• Maxxum 125
• Maxxum 130
• Maxxum 140
• Magnum 180
• Magnum 190
• Magnum 210
• Magnum 225
• Magnum 235-340 (Series 4)

1. 1

   Check the Instrument Panel: Verify if the instrument panel is displaying the correct tractor speed while moving.

2. 2

   Inspect the Radar Connector: Locate the tractor performance monitor radar connector (often designated as C068). Ensure it is connected, not damaged, the pins are in the correct position, and the fit is tight.

3. 3

   Check Fuses: Check the relevant fuse for the speed sensing circuit (often Fuse 9, depending on the model) to ensure it hasn't blown.

4. 4

   Test for Shorts/Opens: Test the wiring harness between the speed sensor/radar and the ECU for a short circuit to ground or an open circuit. Verify that the circuit is receiving the correct reference voltage (usually +12V or +5V depending on the sensor).

5. 5

   Check for Interference: Ensure the tractor is not being calibrated or operated directly under high-voltage lines or radio broadcast towers, which can emit electromagnetic waves that cause electronic interference on the speed sensing circuit.

6. 6

   Check for Related Codes: Look for accompanying codes like Code 2 (Poor/no signal from radar), Code 3 (Radar speed greater than wheel speed), or Code 5 (Wheel speed zero when radar indicates ground speed).

1. 1

   Clear the Condition

   If the transmission was genuinely over-sped (e.g., traveling down a steep incline pulling a heavy load), decrease the engine RPM to approximately 1200 rev/min and select a lower gear.

2. 2

   Repair Wiring

   If the diagnostic checks reveal an open or short circuit in the harness or connector C068, repair or replace the damaged wiring harness/connector.

3. 3

   Replace Sensors

   If the harness and fuses are intact but the voltage/signal remains out of specification, remove and replace the faulty transmission output speed sensor or the performance monitor radar assembly.

4. 4

   Recalibrate

   After replacing the sensor or radar, perform the transmission and hitch calibration procedures. Ensure you are away from electromagnetic interference during calibration.

5. 5

   Test Drive

   Cycle the tractor and test drive to ensure the instrument cluster reads the correct speed and the fault code does not return.