Massey Ferguson 1136.04 – Engine Control Unit (ECU): There Is A Problem With The Engine Module Internal Temperature Sensor Voltage (ECU)
Issue description
The engine management system has detected a voltage reading from the ECU's internal temperature sensor that falls below the acceptable operating threshold, indicating a hardware failure within the module's internal circuitry.
Applies to these machines
43 machines- 4710
- 7724S
- 5712SL
- Interim Tier 4 (2012-2015)
- 7722
- 7722S
- 7615
- 5613
- 5713SL
- 7720S
- 7716
- 7718
- T4
- 7715
- 5710SL
- 7726
- 7616
- 7618
- 5608
- 4708
- 7619
- 7626
- 7726S
- 7624
- 4707
- 4709
- 5711SL
- 7614
- 7718S
- 5610
- 7620
- 7719
- 7714
- 7716S
- T4 (2015-2021)
- 5612
- 7622
- 7720
- Tier 4 (2015-2021)
- 5611
- 7715S
- 5609
- 7724
Check the cause
Verify that the main power and ground connections to the Engine ECU are clean and tight, as a severe voltage drop can cause internal 5V reference circuits to behave erratically.
Look for other voltage-related codes (such as SPN 168 for battery voltage) and resolve those first.
Perform a substitution test by plugging in a known-good replacement ECU to confirm the internal hardware defect.
Repair steps
Disconnect battery
Turn off the ignition and disconnect the tractor's battery (negative terminal first) to prevent electrical spikes.
Locate Engine ECU
Locate the Engine ECU (typically mounted directly to the side of the engine block, utilizing fuel for cooling in some Sisu applications, or on the firewall).
Unplug ECU connectors
Carefully release the locking levers on the main wiring harness connectors and unplug them from the ECU.
Remove defective ECU
Remove the mounting bolts securing the ECU to its bracket and remove the defective module.
Install replacement ECU
Install the replacement ECU and torque the mounting bolts to factory specifications.
Reconnect wiring harnesses
Reconnect the wiring harnesses, ensuring the locking levers are fully seated.
Reconnect battery
Reconnect the battery.
Program new ECU
A new ECU will be blank or lack the specific fuel maps for your tractor. An authorized Massey Ferguson/AGCO dealer must connect the EDT (Electronic Diagnostic Tool) or WinEEM software to flash the correct engine software and calibration files based on your engine's serial number.
Parts you might need
(1)Engine Control Unit (ECU) / Engine Electronic Management (EEM) Module
Varies strictly by exact tractor model and engine serial number. The internal temperature sensor is not sold separately. Defective ECU can often be sent to specialized agricultural electronics repair facilities for internal board-level repair.
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