New Holland ENG 697 – Engine Controller: Engine Controller internal temperature too high.

The Engine Control Unit (ECU) contains an internal temperature sensor designed to monitor the heat of its own circuit board and protect the sensitive electronics from thermal damage. When this sensor detects that the internal temperature has exceeded the maximum safe operating threshold, the system logs ENG 697. This can be caused by actual external overheating, high electrical resistance, or a failure of the internal temperature sensor itself.

• T6000 series
• T7
• T8
• T9
• TJ series
• Puma equivalents
• CR series
• CR9040
• CR9060
• CR9080
• CX series
• CX8080
• CX8090
• B-Series backhoes
• B95B
• B110
• compact excavators
• E30B
• E35B

1. 1

   Verify cold engine ECU internal temperature using the New Holland Electronic Service Tool (EST) or compatible scanner. An impossibly high reading on a cold engine indicates a failed internal sensor.

2. 2

   Inspect the physical mounting location of the Engine Controller for heavy accumulations of chaff, mud, or oily dirt that could insulate the module and prevent heat dissipation.

3. 3

   Check for missing heat shields or exhaust leaks blowing directly onto the ECU.

4. 4

   Inspect the main power and ground pins on the ECU wiring harness for corrosion or loose connections, which can cause high electrical resistance and generate excess heat.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Clear the Area

   Clean the area around the Engine Controller to prevent dirt from entering the wiring harness connectors.

3. 3

   Disconnect Harnesses

   Carefully release the locking levers on the ECU wiring harness connectors and unplug them. Inspect the harness for any melted plastic or burnt pins.

4. 4

   Remove the ECU

   Remove the mounting bolts securing the Engine Controller to the engine block or chassis bracket and remove the unit.

5. 5

   Install Replacement

   Mount the new, refurbished, or repaired Engine Controller and tighten the mounting bolts.

6. 6

   Reconnect

   Reconnect the wiring harnesses, ensuring the locking levers seat fully. Reconnect the battery.

7. 7

   Programming/Calibration

   A new or blank ECU must be flashed with the correct machine-specific software using the New Holland EST diagnostic tool. (Note: If you use a mail-in repair service for your original Bosch ECU, it will retain its programming and is plug-and-play).