New Holland ENG 489 – ENGINE Controller (Engine ECU / ECM): Measured Speed Sensor data low.

The engine control module is receiving a signal from a measured speed sensor (often an auxiliary speed sensor, transmission output speed sensor, or vehicle speed sensor input to the engine) that is lower than expected, erratic, or intermittent.

• T8000 series
• T8040
• T9 series
• T9.390
• T9.600
• T9.700
• TG series
• TG210
• TJ series
• T6000 series
• TM series
• TS series
• Steiger
• Magnum
• CVX
• T4 series
• T5 series
• TSA series

1. 1

   Inspect the speed sensor, the engine harness, and the ECM connectors for bent pins, corrosion, moisture, or physical damage.

2. 2

   Remove the speed sensor and check the magnetic pickup tip for metal shavings or debris, which can distort the signal and cause a 'data low' reading.

3. 3

   Turn the key switch OFF. Disconnect the engine harness from the ECM and the sensor. Measure the resistance from the sensor signal pins to the engine block ground to check for a short circuit.

4. 4

   Measure the resistance from the sensor signal pin to all other pins in the engine harness connector. It should read an open circuit (typically more than 100k ohms). If it does not, the engine harness is shorted and must be replaced.

1. 1

   Disconnect Power

   Turn the key switch OFF and disconnect the battery ground.

2. 2

   Access the Sensor

   Locate the measured speed sensor on the engine block or transmission output housing (location varies depending on whether the ECU is measuring auxiliary engine speed or wheel/transmission speed).

3. 3

   Remove the Sensor

   Unplug the wiring harness connector. Remove the retaining bolt and carefully pull the sensor out of its bore.

4. 4

   Install the New Sensor

   Lubricate the O-ring on the new sensor with clean engine oil. Insert it into the bore and tighten the retaining bolt to OEM torque specs.

5. 5

   Reconnect Wiring

   Reconnect the engine harness to the sensor, ensuring the locking tab clicks into place.

6. 6

   Clear Codes

   Reconnect the battery, turn the key switch ON, and use a diagnostic scan tool (like the CNH Electronic Service Tool) to clear the inactive fault codes.

7. 7

   Test Run

   Start the engine and let it idle for at least 1 minute. Verify that Fault Code ENG 489 remains inactive and does not reoccur.