Case IH 3786 – Engine Control Unit (ECU): Diesel Particulate Filter (DPF): Signal range check flow resistance of the particulate filter - high

DPF Soot Load Overload. The engine control system has detected that the exhaust flow resistance across the DPF has exceeded normal operating parameters, meaning the filter is becoming clogged with soot and requires immediate forced regeneration.

• Farmall
• Quantum V/F/N/CL
• Steiger
• Puma
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)

1. 1

   Check the exhaust line for any physical damage or blockages that could artificially increase backpressure.

2. 2

   Verify the current soot load percentage and the time interval since the last DPF ash service using the electronic service tool (EST) or cluster interface.

3. 3

   Check for related codes, specifically 3787 (Flow resistance - very high) or 3789 (Regeneration duration exceeds maximum allowed duration), which indicate a severely clogged filter.

4. 4

   Test the DPF differential pressure sensor to verify it is reading correctly and ensure its sensor tubes are not melted, cracked, or plugged with soot.

1. 1

   Initiate forced regeneration

   Command a forced regeneration via the instrument cluster interface or the Case IH Electronic Service Tool (EST) because the soot load is overloaded and passive regeneration is no longer sufficient.

2. 2

   Monitor the regeneration

   Allow the machine to complete the forced regeneration cycle. Do not interrupt the process.

3. 3

   Evaluate results

   If the regeneration is successful, the flow resistance will drop, and the code will clear. If the regeneration fails, times out, or the code escalates to 3787, the DPF is too clogged with soot/ash to be burned off in-situ.

4. 4

   Clean or replace the DPF

   If regeneration fails, remove the DPF and have it professionally cleaned (ash removal) or replace it with a new unit.

5. 5

   Reset parameters

   If the DPF is cleaned or replaced, you must reset the DPF parameters via the Case IH Service Tool so the ECU knows the filter is empty.