CLAAS Id7741h / 7741h (636 02) – ENG (A15): Signal of the position sensor of the high pressure pump non valid.

The engine control unit has detected electrical noise or an invalid signal pattern on the high-pressure fuel pump position sensor circuit. Because the pump position signal is invalid, the engine calculator defaults to using the signal from the crankshaft position sensor to determine the piston's position. The primary symptom is an extended engine start/cranking time.

• Axion 810
• Axion 820
• Axion 830
• Axion 840
• Axion 850
• Arion 410
• Arion 430
• Arion 520
• Arion 530
• Arion 550
• Arion 620
• Arion 640
• Arion 650

1. 1

   Locate the high-pressure pump position sensor, identified as component B232 in CLAAS wiring schematics.

2. 2

   Check the wiring harness linking the B232 sensor to the ENG (A15) module for continuity, open circuits, or short-circuits to ground.

3. 3

   Inspect for electrical noise on the Pump Position Sensor + (cc# 172) and Pump Position Sensor - (cc# 173) circuits.

4. 4

   Check the sensor connector for corrosion, moisture, or loose pins.

5. 5

   Check the internal resistance of the B232 sensor.

6. 6

   Verify the power supply and ground of the ENG (A15) engine module.

1. 1

   Clean area

   Ensure the engine is off and the key is removed. Clean the area around the high-pressure fuel pump to prevent debris from entering the system.

2. 2

   Disconnect wiring

   Disconnect the wiring harness connector from the pump position sensor (B232).

3. 3

   Remove sensor

   Remove the sensor from the high-pressure pump housing.

4. 4

   Lubricate O-ring

   Coat the O-ring of the new sensor with high-temperature grease (e.g., JDT405 High Temperature Grease).

5. 5

   Install sensor

   Install the new sensor into the pump housing.

6. 6

   Tighten sensor

   Tighten the sensor to the specified torque of 14 N·m to 15 N·m (10 to 11 lb-ft).

7. 7

   Reconnect wiring

   Reconnect the sensor wiring connection.

8. 8

   Clear codes and test

   Clear the fault codes from the ENG (A15) module using a diagnostic tool and test start the engine to verify that the extended cranking issue is resolved.