Massey Ferguson 00.01.64 – Dash: Issue With Hydraulic Oil Temperature Signal Voltage

The voltage signal being sent from the hydraulic oil temperature sensor is outside of the expected operating range (e.g., an open circuit, a short to ground, or a short to power).

• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S
• Tier 4 (2015-2021)
• 7700 Series

1. 1

   Inspect the wiring harness connecting the hydraulic oil temperature sensor to the Dash module for chafed wires, melted insulation, or breaks

2. 2

   Disconnect the sensor and inspect the pins for corrosion, moisture, or pushed-out pins that could cause high resistance or an open circuit

3. 3

   Turn the key to the ON position (engine off) and use a multimeter to check the reference voltage at the sensor connector to ensure the Dash is supplying correct voltage

4. 4

   Measure the internal resistance of the hydraulic oil temperature sensor across its terminals to check for an internal failure (open circuit or dead short)

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the negative battery terminal to prevent electrical shorts during the repair.

2. 2

   Locate the Sensor

   Locate the hydraulic oil temperature sensor (typically threaded into the hydraulic priority block, transmission housing, or auxiliary hydraulic lines depending on the exact model configuration).

3. 3

   Wiring Repair

   If the diagnostic checks revealed a broken wire or damaged connector, splice in a new connector pigtail or repair the wire using weather-sealed heat shrink connectors.

4. 4

   Sensor Replacement

   If the sensor itself failed: Place a clean catch pan under the sensor location to catch any hydraulic oil that may leak out. Unplug the electrical connector. Use a wrench to carefully unthread the old temperature sensor. Thread the new OEM sensor into the port. Tighten it to the manufacturer's specified torque (do not over-tighten, as these are often brass or hollow-body sensors).

5. 5

   Reassembly

   Reconnect the electrical connector until it clicks into place.

6. 6

   Testing

   Reconnect the battery. Start the tractor and allow it to reach operating temperature. Verify that the Dash no longer displays fault code 00.01.64. Check the sensor area for any hydraulic fluid leaks and top off the hydraulic oil if necessary.