Case IH 17644 (F-3285-03) - ECU – Engine Control Unit (ECU): Differential pressure sensor: sensor reporting signal range check is too high.

This indicates that the control module is receiving a voltage or signal from the exhaust gas differential pressure sensor (used to monitor the DPF/SCR aftertreatment system) that exceeds the maximum allowable threshold. This condition is typically caused by a short circuit to a power source, an internal failure of the sensor itself, or an extreme physical blockage in the exhaust system causing an implausibly high pressure reading.

• VESTRUM CVX
• Case IH Austoft 9900 Sugarcane Harvesters
• Farmall
• Maxxum
• Puma
• Magnum

1. 1

   Inspect the wiring harness and the connector at the differential pressure sensor for chafing, corrosion, or a short circuit to battery voltage.

2. 2

   Use the CNH Electronic Service Tool (EST) to monitor the live voltage/pressure reading of the sensor. If the value is stuck at the maximum limit even when the engine is off, it is an electrical or sensor fault.

3. 3

   Disconnect the pressure hoses/tubes running from the exhaust pipe to the sensor. Check them for melting, cracking, or severe soot/carbon blockages.

4. 4

   Verify if the DPF or SCR is severely clogged, which could cause an actual overpressure situation.

1. 1

   Prepare machine

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

2. 2

   Locate sensor

   Locate the exhaust gas differential pressure sensor, typically mounted near the DPF/SCR canister on the aftertreatment assembly.

3. 3

   Unplug electrical connector

   Carefully unplug the electrical connector from the sensor.

4. 4

   Disconnect pressure hoses

   Disconnect the primary and secondary pressure hoses from the bottom of the sensor.

5. 5

   Clear pressure hoses

   Blow compressed air through the disconnected hoses (blowing away from the sensor, toward the exhaust) to ensure they are completely clear of soot and condensation.

6. 6

   Remove faulty sensor

   Remove the mounting bolts and remove the faulty sensor.

7. 7

   Install new sensor

   Install the new differential pressure sensor and secure the mounting bolts.

8. 8

   Reconnect pressure hoses

   Reconnect the pressure hoses, ensuring they are not crossed (high-pressure side to the high port, low-pressure side to the low port).

9. 9

   Reconnect electrical connector and battery

   Reconnect the electrical connector and the machine's battery.

10. 10

    Clear codes and regenerate

    Connect the CNH EST diagnostic tool, clear the 17644 (F-3285-03) fault code, and perform a stationary/forced regeneration to verify the repair and ensure the exhaust system is operating within normal pressure parameters.