Case IH 3814 – Engine Control Unit (ECU): ECU temperature sensor: SPI Error ECU temperature sensor (LM71)

The ECU has detected an internal Serial Peripheral Interface (SPI) communication error with its integrated LM71 temperature sensor chip, or the internal voltage for the sensor is not plausible.

• skid steer
• Magnum
• Steiger
• Puma
• Maxxum
• Farmall
• Axial-Flow series
• SR220
• SR250
• SV250
• SV300
• TR320
• TV380

1. 1

   Turn the key ON (Engine OFF) and verify if the fault is currently active

2. 2

   Visually inspect the main ECU harnesses and connectors for damage, bent pins, or dislocated pins (poor power or ground supply can cause erratic internal voltage readings)

3. 3

   Connect the CNH Electronic Service Tool (EST) and check if the ECU software is corrupted

1. 1

   Re-initialize the ECU

   Using the EST service tool, attempt to re-initialize the ECU and load the appropriate data-set for your specific engine type. (Note: A call to CNH Technical Support (TSS) may be required to get an authorization code for the ECU initialization download).

2. 2

   Re-test

   Cycle the key and check to see if the fault code has cleared.

3. 3

   Replace the ECU

   If the fault code does not clear after a software re-initialization, the internal LM71 temperature sensor has failed. Because this sensor is permanently integrated into the ECU's internal circuit board, it cannot be serviced separately. You must replace the entire Engine Control Unit.

4. 4

   Program the New ECU

   Install the new ECU and use the EST tool to flash it with the correct dataset for the machine's serial number.