Case IH 3797 (F-3251-03) - ECU – ENGINE ECU: Diesel Particulate Filter (DPF) Pressure Sensor: SRC High for Particulate Filter Differential Pressure Sensor

The engine control system has detected that the voltage signal (Signal Range Check / SRC) from the DPF differential pressure sensor is higher than the maximum expected threshold, typically indicating an open circuit, a short to a high-voltage source in the wiring harness, or an internal failure of the sensor itself.

• VESTRUM CVX
• Farmall series (40, 45, 50, 115U)
• Maxxum series
• Puma series
• Steiger series
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)

1. 1

   Verify battery and alternator are outputting correct voltage, as low voltage can cause erroneous codes.

2. 2

   Inspect physical pressure hoses/lines connecting the DPF to the sensor for detachment, cracks, melting, or soot/ash blockages.

3. 3

   Inspect the sensor's electrical connector and engine wiring harness for corrosion, bent pins, chafing, or shorts/open circuits.

4. 4

   Test the sensor's 5-volt reference supply and ground at the connector using a multimeter.

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Locate the Sensor

   Locate the DPF differential pressure sensor, which is typically mounted on a bracket near the Diesel Particulate Filter assembly in the exhaust stream.

3. 3

   Remove Hoses

   Carefully unclamp and disconnect the pressure lines from the sensor. Blow out the disconnected lines with low-pressure compressed air to ensure they are free of soot or condensation blockages. Replace the hoses if they are brittle.

4. 4

   Remove the Sensor

   Disconnect the electrical harness connector. Remove the mounting bolts securing the faulty differential pressure sensor and remove it from the machine.

5. 5

   Install the New Part

   Mount the new replacement sensor. Reattach the pressure hoses to their correct respective ports (upstream/downstream) and plug in the electrical connector until it clicks.

6. 6

   Clear Codes

   Reconnect the battery. Use the Case IH Electronic Service Tool (EST) to clear the stored 3797 fault code from the Engine ECU.

7. 7

   Perform Regeneration

   Perform a manual or service DPF regeneration to verify that the new sensor accurately reads the pressure differential and that the exhaust system functions normally without throwing the code again.