Case IH 3625 – Engine Control Unit (ECU): Crank case pressure sensor - Voltage below lower limit

The Engine Control Unit (ECU) has detected a fault associated with the crankcase pressure sensor. Specifically, the signal voltage returning to the ECU has dropped below the minimum threshold of 0.2 Volts. Cause: The crankcase pressure signal to the ECU is too low, which is typically caused by either a faulty sensor or a wiring failure (such as an open circuit or a short to ground).

• 5140
• 6140
• 6150
• 7140
• 7150
• 7240
• 7250
• 8240
• 8250
• 9240
• 9250
• 1021G
• 1121F
• 1121G
• TV450B

1. 1

   Use an Electronic Service Tool to verify that fault code 3625 is currently present and active.

2. 2

   Check that the crankcase pressure sensor is installed correctly and securely.

3. 3

   Inspect the wiring harness leading to the sensor's 3-pin connector for physical damage, chafing, or melted wires that could cause a short to ground.

4. 4

   Back-probe the sensor connector to verify if the voltage is genuinely below 0.2 V. If the reference voltage from the ECU is present but the signal wire is dead, the sensor has likely failed internally.

1. 1

   Disconnect Battery/Power

   Ensure the machine is turned off and the key is removed to prevent electrical spikes.

2. 2

   Locate the Sensor

   Locate the crankcase pressure sensor on the engine block (refer to the engine timing/crankcase section of your specific machine's service manual).

3. 3

   Inspect the Connector

   Unplug the 3-pin electrical connector. Check for moisture, oil intrusion, or corroded pins. Clean with electrical contact cleaner if necessary.

4. 4

   Test the Harness

   If the connector is clean, test the continuity of the wiring harness back to the ECU. Repair any damaged sections of the harness.

5. 5

   Replace the Sensor

   If the wiring harness is in good condition and the sensor is installed correctly but the fault persists (voltage remains < 0.2 V), the sensor itself is defective. Remove the old sensor and install the replacement.

6. 6

   Clear Codes

   Reconnect the 3-pin harness, power on the machine, and use the Electronic Service Tool to clear the inactive fault code. Run the engine to ensure the code does not return.