Case IH 3881 (F-3507-04) - ECU – Engine Control Unit (ECU): ECU 12/24 volt actuator supply 1 is shorted to ground

ECU 12/24 volt actuator supply 1 is shorted to ground. The specific circuit for supply 1 corresponds to pins 2.05, 2.17, 2.18, and 2.19 on the ECU. The fault is also described in CNH EDC reference guides as a Short circuit to ground error at high side actuator relay with index x = 0.

• VESTRUM CVX
• Magnum (CVT/CVX)
• Maxxum (CVX)
• Optum (CVX)
• Puma (CVX/CVX EP, Puma X)
• Vestrum
• Steiger
• Axial-Flow Combines
• Farmlift
• Graders (836C, 856C)
• Wheel Loaders (621G, 721G, 821G, 1021G, 1121G)

1. 1

   Use an Electronic Service Tool to confirm the presence of code 3881 (F-3507-04).

2. 2

   Turn the ignition off and disconnect the vehicle engine harness from the Bosch MD1CE101 ECU.

3. 3

   Using a multimeter, test for continuity to chassis ground on the engine harness side at pins 2.05, 2.17, 2.18, and 2.19.

4. 4

   Locate the high side actuator relay (index x = 0) and test it for internal shorts to ground.

5. 5

   Trace the wiring harness from the ECU pins to the actuator relay, looking for chafed insulation, melted wires, or pinch points where the wire may be grounding out against the chassis.

1. 1

   Disconnect battery

   Disconnect the machine's battery to prevent electrical damage during repair.

2. 2

   Repair or replace wiring harness

   If the multimeter test reveals a short in the wiring harness, carefully open the wire loom and repair the damaged section of the wire corresponding to the supply 1 circuit, or replace the engine wiring harness entirely.

3. 3

   Replace actuator relay

   If the wiring is intact but the high side actuator relay is internally shorted, remove and replace the faulty relay.

4. 4

   Reconnect harness

   Reconnect the engine harness to the Bosch MD1CE101 ECU.

5. 5

   Reconnect battery

   Reconnect the battery.

6. 6

   Clear codes and verify

   Turn the ignition on and use the Electronic Service Tool to clear the fault codes. Cycle the ignition and run the machine to verify the code does not return.