CLAAS Id7730h / 7730h (157 04) – ENG (A15): Input voltage of the fuel pressure sensor in the common rail low.

The engine control module detects that the signal voltage coming from the common rail fuel pressure sensor is below the minimum acceptable threshold. This typically indicates a short to ground in the sensor circuit, a failed sensor, or a wiring harness issue.

• Axion 810
• Axion 820
• Axion 830
• Axion 840
• Axion 850
• Axion 960
• Arion 410
• Arion 420
• Arion 430
• Arion 510
• Arion 520
• Arion 530
• Arion 540
• Arion 610
• Arion 620
• Arion 630
• Arion 640
• Arion 650

1. 1

   Inspect the wiring harness connecting the fuel pressure sensor (designated as component B42 or B042) to the ENG (A15) module. Look for chafing, pinched wires, or a short circuit to ground.

2. 2

   Verify the power supply and output signal of the fuel pressure sensor. Check the connector pins for corrosion or poor contact.

3. 3

   Verify that the engine control module is outputting the correct 5V reference voltage to the sensor.

1. 1

   Safety First

   Turn off the engine and allow the high-pressure fuel system to depressurize completely before loosening any fittings.

2. 2

   Locate the Sensor

   Locate the fuel pressure sensor (B42) threaded into the common rail fuel distribution manifold.

3. 3

   Inspect Wiring

   Disconnect the electrical connector from the sensor. Inspect the terminals. Use a multimeter to test the wiring harness back to the ENG (A15) module for continuity and ensure there is no short to ground.

4. 4

   Replace the Sensor

   If the wiring harness and ECU reference voltage test good, the sensor itself has failed internally. Unthread the old B42 sensor from the common rail and install the replacement sensor. Torque to the manufacturer's specification.

5. 5

   Clear Codes

   Reconnect the wiring harness, turn the key on, and use the CLAAS Diagnostic System to clear the Id7730h / 157 04 fault code.

6. 6

   Test Run

   Start the engine and verify that the power reduction mode (50% derate) is deactivated and that fuel pressure readings are accurate in the diagnostic tool.