Case IH 3086 – Engine Control Unit (ECU / ECM): Injector Booster Voltage C2 - SOURCE HIGH

The Engine Control Unit (ECU) has detected that the capacitor charge or booster voltage for the second bank of fuel injectors is higher than the commanded or expected threshold. Alternatively, the ECU is receiving a signal voltage from the air filter restriction/pressure sensor that falls below the minimum acceptable threshold.

• Magnum
• Steiger
• Maxxum
• Axial-Flow 5130
• Axial-Flow 6130
• Axial-Flow 7130
• Axial-Flow 8240

1. 1

   For Code 3086 (Injector Booster Voltage C2): Inspect the engine wiring harness leading to the fuel injectors (specifically Bank 2 / Circuit 2) for chafing, melting, or exposed wires shorting to a power source.

2. 2

   For Code 3086 (Injector Booster Voltage C2): Ohm test the fuel injectors on that circuit to ensure the solenoids are not internally shorted.

3. 3

   For Air Filter Pressure Sensor (Voltage Low): Visually inspect the engine air filter housing and the physical condition of the air filter pressure sensor.

4. 4

   For Air Filter Pressure Sensor (Voltage Low): Disconnect the sensor and check the connector for corrosion, moisture, or pushed-out pins.

5. 5

   For Air Filter Pressure Sensor (Voltage Low): Turn the key ON (engine OFF) and use a digital multimeter to verify a 5V reference signal and a good ground at the sensor connector.

6. 6

   For Air Filter Pressure Sensor (Voltage Low): Check the signal wire for continuity back to the ECU and ensure it is not shorted to ground.

1. 1

   Turn off the machine and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Locate the air filter pressure sensor on the intake piping or air cleaner housing.

3. 3

   If the wiring harness is damaged (shorted to ground): Cut out the damaged section of the harness and solder/heat-shrink a new section of wire, or splice in a replacement sensor pigtail connector.

4. 4

   If the wiring and 5V reference test good: The sensor itself has failed internally. Remove the retaining screws or unthread the sensor from the housing.

5. 5

   Install the new Air Filter Pressure Sensor and plug in the electrical connector.

6. 6

   Reconnect the battery, turn the key ON, and use a diagnostic tool (such as the CNH Electronic Service Tool) to clear the inactive fault codes.