New Holland NH 3087 – Engine Control Unit (ECU): Injector Booster Voltage C2 - SOURCE LOW

The engine control module has detected an abnormally low voltage on the Bank 2 (C2) injector booster circuit. This is almost always caused by a short to ground in the Bank 2 injector wiring harness, an internally shorted fuel injector on that bank, or a failure of the booster capacitor inside the ECU itself.

• FR Series Forage Harvesters (FR480 to FR850)
• Tractors (T6000 series, TS-A series, TS135A)
• Machines with NEF Tier 2 / Tier 3 engines

1. 1

   Visually inspect the engine wiring harness, specifically the injector harness for Bank 2 (C2), looking for chafed wires, melted insulation, or areas rubbing against the engine block that could cause a short to ground.

2. 2

   Perform an injector isolation test: Disconnect the electrical connectors from the Bank 2 injectors one at a time. Cycle the key and check if the active fault changes from 'SOURCE LOW' to an open circuit code. If it changes, the disconnected injector is internally shorted.

3. 3

   Use a multimeter to measure the resistance of each Bank 2 injector to verify they are within OEM spec and to ensure there is no continuity between the injector pins and the injector body/engine ground.

4. 4

   Disconnect the 36-way and 89-way connectors at the EDC7 ECU. Inspect the pins for corrosion, moisture intrusion, or pushed-out terminals.

5. 5

   If the wiring harness tests good (no shorts to ground) and all injectors pass resistance testing, suspect an internal failure of the booster capacitor inside the EDC7 ECU.

1. 1

   Turn off the machine's ignition and disconnect the negative battery cable.

   Turn off the machine's ignition and disconnect the negative battery cable to prevent electrical arcing.

2. 2

   Gain access to the engine valve cover and the EDC7 ECU mounting location.

   Gain access to the engine valve cover and the EDC7 ECU mounting location.

3. 3

   Replace the faulty injector if isolated during diagnostic checks.

   If the diagnostic checks isolated a shorted fuel injector, remove the high-pressure fuel lines and replace the faulty injector. Torque all fittings to OEM specifications.

4. 4

   Repair the affected section of the wiring harness if chafed or damaged.

   If the wiring harness is chafed or damaged, repair the affected section. If the damage is near the ECU connectors, use an OEM Bosch repair pigtail harness to splice in new wiring.

5. 5

   Remove and repair or replace the EDC7 ECU if deemed faulty.

   If the ECU is deemed faulty (internal capacitor failure), remove the EDC7 ECU. You must either send it to a specialized heavy-duty electronics repair facility for remanufacturing or replace it with a new, programmed unit.

6. 6

   Reconnect all electrical connectors and the negative battery cable.

   Reconnect all electrical connectors and the negative battery cable.

7. 7

   Clear the inactive fault code and verify the repair.

   Use a diagnostic tool (such as the CNH Electronic Service Tool) to clear the inactive NH 3087 fault code and verify the repair by running the engine.