New Holland ENG 3814 – Engine Control Unit (ECU) / EDC: EDC - ECU temperature sensor: SPI Error ECU temperature sensor (LM71)

The ECU detects a communication failure, an implausible internal voltage, or a complete loss of signal from its internal temperature sensor (LM71) via the internal SPI bus.

• Workmaster 50
• T6
• T7
• T8
• T9
• CR9090
• CX8080
• CX8090
• W50C
• W60C
• W70C
• W80C

1. 1

   Connect the Electronic Service Tool (EST) and check if the fault is currently active or stored.

2. 2

   Clear the fault code and cycle the machine's power. Operate the machine to see if the code returns, as it may have been a momentary voltage glitch.

3. 3

   Check if there is a newer software/firmware flash available for the Engine ECU that addresses false LM71 SPI errors.

4. 4

   Ensure the ECU is not being subjected to abnormal external heat sources, such as missing heat shields or exhaust leaks, that could cause the sensor to read erratically.

1. 1

   Turn off the machine and disconnect the battery ground.

2. 2

   Locate the Engine Control Unit (ECU A-9000) on the machine.

3. 3

   Disconnect the main wiring harness connectors (e.g., X-9001) from the ECU.

4. 4

   Unbolt and remove the faulty ECU.

   The LM71 sensor is soldered to the internal motherboard of the ECU and cannot be serviced or replaced individually.

5. 5

   Install the replacement Engine Control Unit.

6. 6

   Reconnect the wiring harnesses and battery.

7. 7

   Connect the New Holland EST (Electronic Service Tool) and flash/program the new ECU with the correct engine dataset and machine configuration.