New Holland NH 3084 – Engine Control Unit (ECU) / Bosch EDC7: Injector Booster Voltage C1 - SOURCE HIGH

The voltage measured on the specific booster circuit (Capacitor Bank 1) exceeds the maximum allowable threshold. This condition is usually caused by a short circuit to battery power within the injector wiring harness, a shorted fuel injector solenoid, or a hardware failure inside the engine controller itself (a blown or shorted internal capacitor circuit).

• T-Series Tractors (e.g., T5, T6, T7, TM series)
• CR Series Combines (e.g., CR6090, CR7090)
• Crawler Dozers (e.g., D180 Tier 3)
• Wheel Loaders
• Skid Steers

1. 1

   Verify system voltage to ensure the alternator is not overcharging the electrical system, which can trigger booster voltage faults

2. 2

   Disconnect the engine wiring harness from the ECU and injectors, and inspect for chafing, melted insulation, or pinched wires

3. 3

   Use a multimeter to check for continuity between the injector supply wires and any 12V/24V power source (short to power)

4. 4

   Measure the resistance of each fuel injector coil on Bank 1 to check for internal shorts to the injector body (ground) or abnormal resistance

5. 5

   Inspect the EDC7 ECU connector pins for corrosion, water ingress, or bent pins that could bridge circuits and cause false high-voltage readings

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the negative battery terminal to prevent electrical damage.

2. 2

   Isolate the Circuit

   Disconnect the wiring harness from the Bank 1 fuel injectors and the EDC7 ECU.

3. 3

   Test and Repair Wiring

   If the multimeter test reveals a short to power in the harness, trace the harness back to the point of damage. Repair the damaged wires using proper soldering and heat-shrink techniques, or replace the entire injector wiring harness if the damage is extensive.

4. 4

   Replace Faulty Injectors

   If an injector fails the resistance test (indicating an internal short), remove and replace the faulty fuel injector.

5. 5

   ECU Replacement

   If the wiring harness and all injectors test perfectly fine, the fault is an internal hardware failure of the EDC7 ECU's booster capacitor. The ECU must be removed and either sent to a specialized module repair facility or replaced with a new unit.

6. 6

   Reassembly and Calibration

   Reconnect all harnesses. Reconnect the battery. Use the New Holland Electronic Service Tool (EST) to clear the inactive fault codes and, if the ECU or injectors were replaced, program the new component data into the system. Run the engine to verify the fix.