Case IH 17671 (F-519694-12) - ECU – Engine Control Unit (ECU) / Electronic Diesel Control (EDC): Differential pressure sensor: fault check for the pressure sensor plausibility at cold conditions only.

The engine control system runs a plausibility check on the Exhaust Gas / DPF (Diesel Particulate Filter) Differential Pressure Sensor when the machine is cold (typically at key-on, engine-off, before exhaust pressures build). During this cold state, the differential pressure should read at or very near zero. If the sensor reports a signal range that is unexpectedly low, out of bounds, or mathematically impossible compared to ambient atmospheric pressure, the system flags it as implausible and logs this code.

• VESTRUM CVX
• Austoft 9000 Series Sugar Cane Harvesters
• Austoft 9900 Series Sugar Cane Harvesters
• Farmall
• Maxxum
• Puma
• CVX

1. 1

   Inspect the two pressure tubes/hoses running from the exhaust pipe/DPF to the differential pressure sensor for melted lines, cracks, blockages from soot/carbon buildup, or disconnected hoses.

2. 2

   Disconnect the sensor and inspect the wiring harness and connector pins for corrosion, moisture intrusion, or chafed wires that could cause a voltage drop or short.

3. 3

   Using the Case IH Electronic Service Tool (EST), monitor the live data for the Differential Pressure Sensor at key-on, engine-off (cold condition). The reading should be approximately 0 kPa / 0 psi.

4. 4

   Check for accompanying codes such as 17644 (undervoltage), 17645 (signal too high), or 17643 (internal fault) which further confirm a dead sensor or wiring short.

1. 1

   Preparation

   Turn off the machine, remove the key, and disconnect the negative battery terminal. Ensure the exhaust system is completely cool to the touch.

2. 2

   Locate the Sensor

   Locate the Exhaust Gas Differential Pressure Sensor, which is typically mounted on a bracket near the DPF or SCR aftertreatment assembly.

3. 3

   Disconnect Electrical

   Depress the locking tab and disconnect the electrical pigtail from the sensor.

4. 4

   Remove Hoses

   Carefully remove the upstream and downstream pressure hoses from the sensor nipples. Note: Mark the hoses (e.g., "High" and "Low") to ensure they are not swapped during reassembly, as reversing them will immediately trigger new fault codes.

5. 5

   Remove Sensor

   Unbolt the sensor from its mounting bracket (usually held by 8mm or 10mm bolts) and remove it from the machine.

6. 6

   Install New Sensor

   Bolt the new OEM sensor to the bracket.

7. 7

   Reconnect Hoses & Wiring

   Reattach the pressure hoses to their correct respective ports and ensure they are clamped tightly. Reconnect the electrical harness until it clicks.

8. 8

   Relearn/Reset Procedure

   Reconnect the battery. Connect the Case IH EST diagnostic software. Clear the inactive 17671 fault code. You must perform a "differential pressure sensor restart" or adaptation reset in the engine's special functions menu so the ECU learns the new sensor's zero-value baseline.