Case IH 242 – ENG (Engine Control Module / ECM): Vehicle Speed Signal intermittent / tampering

The Engine Control Module (ECM) has detected an intermittent connection, an abnormal rate of change, or a tampering event regarding the vehicle speed signal. If the ECM detects that the signal drops out, fluctuates erratically, or indicates an attempt to defeat the road speed governor (tampering), it logs this code. When active, the engine speed operating range is often limited, and features like Cruise Control and Gear-Down Protection are disabled.

• MX Magnum
• STX Steiger
• Magnum
• Steiger
• STX
• Puma
• MXU
• Maxxum
• Axial-Flow

1. 1

   Verify ECM Settings: Check that the feature settings for 'VSS Anti-Tampering', application type, and transmission type are set correctly in the ECM using an electronic service tool.

2. 2

   Operator Habits: Note that driving techniques, such as operating the machine for extended periods of time in lower gears, can sometimes falsely trigger the anti-tampering logic.

3. 3

   Visual Tampering Inspection: Inspect the VSS and its wiring harness for signs of physical tampering, such as disconnected wires or aftermarket inline bypass devices.

4. 4

   Wiring and Connector Check: Inspect the VSS electrical connector at the transmission and the ECM chassis connector (specifically noting pins 27 and 36) for corrosion, moisture, pushed-back pins, or chafed wires.

1. 1

   Turn off the ignition key and disconnect the battery

   Ensure safety and prevent electrical shorts.

2. 2

   Locate the Vehicle Speed Sensor

   Typically mounted on the rear of the transmission housing (tailshaft).

3. 3

   Disconnect the electrical connector from the VSS

   Inspect the harness side for any corrosion or damage.

4. 4

   Remove the retaining bolt holding the VSS in place

   Carefully pull the sensor out of the transmission housing.

5. 5

   Install the new Vehicle Speed Sensor

   Tighten the retaining bolt to OEM torque specifications.

6. 6

   Reconnect the electrical connector

   Ensure the weather seal is intact and the locking tab clicks into place.

7. 7

   Reconnect the battery

8. 8

   Validate the repair

   Perform a key cycle, start the engine, and let it idle for at least 1 minute. The fault code status should change to INACTIVE. Use an electronic diagnostic tool to execute the 'Reset All Faults' command and clear the code.