New Holland ENG 491 – ENGINE: Wastegate 2 voltage is too high.

This indicates that the signal voltage from the Wastegate 2 actuator/sensor circuit has exceeded the maximum expected threshold. This is typically caused by a short to power, an open ground circuit in the wiring harness, or an internal failure of the wastegate actuator's electrical component.

• T8010
• T8020
• T8030
• T8040
• T8050
• T9 Series
• Magnum series
• CR9090
• CX8080 Elevation
• CX8090 Elevation

1. 1

   Visually inspect the wiring harness running from the Engine ECU to the Wastegate 2 actuator for chafing, melted insulation, or pinched wires that could cause a short to a 12V/5V power source.

2. 2

   Disconnect the Wastegate 2 connector and the Engine ECU connector. Check for corrosion, moisture, pushed-back pins, or damaged terminals.

3. 3

   Use a multimeter to test the signal wire for a short to power. Test the ground circuit for an open condition (high resistance), as an open ground will often cause the sensor voltage to default to its highest limit.

4. 4

   If the wiring and connectors test good, check for an internal short or failure within the Wastegate 2 actuator itself.

1. 1

   Power Down

   Turn off the machine's ignition and disconnect the battery master switch to prevent electrical spikes.

2. 2

   Access the Turbocharger

   Locate the secondary turbocharger or the specific Wastegate 2 actuator on the engine exhaust manifold.

3. 3

   Repair Wiring (If Applicable)

   If the diagnostic tests revealed a short or open circuit in the harness, repair the damaged section of the wire or replace the pigtail connector. Use heat-shrink butt connectors to ensure a weather-tight seal.

4. 4

   Replace the Actuator (If Applicable)

   If the harness is intact, remove the mounting bolts and linkage clip securing the Wastegate 2 actuator. Install the new actuator and calibrate it if required by the specific engine service manual. (Note: On some VGT or bi-turbo setups, the actuator may be integrated into the turbocharger, requiring a complete turbo replacement).

5. 5

   Reassemble and Clear Codes

   Reconnect all electrical plugs and battery power. Use a diagnostic tool (such as the New Holland Electronic Service Tool) to clear the ENG 491 inactive fault code from the Engine ECU.

6. 6

   Test Run

   Start the engine and monitor the wastegate voltage parameters under load to ensure they remain within the normal operating range.