Deutz-Fahr 515 – ECM: HCI Pressure Sensor Low Limit

The Engine Control Module (ECM) has detected that the pressure sensor located immediately after the Hydrocarbon Injection (HCI) dosing valve is reporting a pressure value below the minimum acceptable threshold. This lower limit value exceeded error (FMI 4) signifies that the sensor's signal voltage is below the normal operating range, suggesting a short circuit to ground, an open circuit, or a complete failure of the sensor itself. The HCI system is critical for injecting fuel into the exhaust stream to initiate and maintain Diesel Particulate Filter (DPF) regeneration.

• Deutz TCD 4.1 L4
• Deutz TD 2.9 L4
• Deutz TCD 3.6 L4
• Deutz TCD 6.1 L6
• Deutz TCD 7.8 L6
• Genie GTH-1256
• Genie GTH-5519
• Genie GTH-1056

1. 1

   Visually inspect the wiring harness and connector for the HCI downstream pressure sensor for chafing, corrosion, pinched wires, or loose connections.

2. 2

   Use a multimeter to test the sensor's circuit for continuity and check for a short circuit between the signal wire and ground.

3. 3

   Verify the correct voltage supply to the sensor from the ECM.

4. 4

   Use diagnostic software (like Deutz SerDia) to check live data from the pressure sensor for an unchanging or zero-pressure reading while the engine is running.

5. 5

   Ensure the HCI dosing valve and the line leading to the sensor are not physically blocked or clogged, which could prevent pressure from building.

1. 1

   Ensure safety

   Turn off the machine, follow all lockout/tagout procedures, and allow the exhaust system to cool completely before beginning work.

2. 2

   Locate components

   Identify the HCI dosing valve and the downstream pressure sensor on the exhaust aftertreatment system.

3. 3

   Replace pressure sensor

   If the sensor is identified as faulty, disconnect the electrical connector, carefully unscrew the old pressure sensor from its mounting boss, install the new sensor to the manufacturer's specified torque, and securely reconnect the electrical connector.

4. 4

   Clear fault codes

   Use a compatible diagnostic tool to clear the active and inactive fault codes from the ECM.

5. 5

   Perform system test

   Start the engine and bring it to operating temperature. Initiate a service regeneration to verify that the HCI system is operating correctly and the fault code does not return.