Case IH 3877 (F-3508-14) - ECU – Engine Control Module (ECM) / Bosch MD1CE101 ECU: ECU 12/24 volt actuator supply 1 is shorted to battery voltage

The Engine Control Module (ECM) has detected that the voltage on the actuator supply 1 circuit is too high, meaning it is receiving unintended battery voltage. This specific supply circuit corresponds to pins 2.05, 2.17, 2.18, and 2.19 on the engine control unit.

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1. 1

   Turn the ignition key to the OFF position and disconnect the engine wiring harness from the Bosch MD1CE101 ECU.

2. 2

   Locate pins 2.05, 2.17, 2.18, and 2.19 on the harness connector.

3. 3

   Turn the ignition key to the ON position (do not start the engine). Use a multimeter to measure the voltage between the harness pins (2.05, 2.17, 2.18, 2.19) and a known good ground. If battery voltage (12V or 24V) is present, there is a short to power in the wiring harness.

4. 4

   Visually inspect the wiring harness routing from the ECU to the engine actuators. Look for chafing, melted insulation, or pinched wires that could short the actuator supply wire to a live 12V/24V power source.

5. 5

   Disconnect the actuators powered by supply 1 one by one. If the short to battery voltage disappears when a specific actuator is unplugged, that actuator is internally shorted.

1. 1

   Turn off the machine and disconnect the battery negative terminal to ensure safety.

   Turn off the machine and disconnect the battery negative terminal to ensure safety.

2. 2

   If the diagnostic checks revealed a short in the wiring harness, trace the harness from the ECU to the actuators on Supply 1.

   If the diagnostic checks revealed a short in the wiring harness, trace the harness from the ECU to the actuators on Supply 1.

3. 3

   Repair the damaged section of the wiring harness by splicing and heat-shrinking the affected wires. If the harness is severely melted or damaged, replace the entire engine wiring harness.

   Repair the damaged section of the wiring harness by splicing and heat-shrinking the affected wires. If the harness is severely melted or damaged, replace the entire engine wiring harness.

4. 4

   If an actuator was found to be internally shorted to power during the diagnostic phase, replace the faulty actuator.

   If an actuator was found to be internally shorted to power during the diagnostic phase, replace the faulty actuator.

5. 5

   Reconnect all harness connectors to the actuators and the Bosch MD1CE101 ECU.

   Reconnect all harness connectors to the actuators and the Bosch MD1CE101 ECU.

6. 6

   Reconnect the battery negative terminal.

   Reconnect the battery negative terminal.

7. 7

   Turn the key ON and use a diagnostic tool to clear the fault code 3877 (F-3508-14).

   Turn the key ON and use a diagnostic tool to clear the fault code 3877 (F-3508-14).

8. 8

   Start the engine and verify that the fault code does not return and the machine operates normally.

   Start the engine and verify that the fault code does not return and the machine operates normally.