1) Why DPFs fail (root causes)

A DPF blockage is rarely the root problem. In most cases it’s a consequence of upstream faults: air-mix errors,
excessive fuelling, or poor calibrations. Fix the cause first; the delete alone won’t restore reliability.

• Air regulation faults: EGR sticking/leaking; boost leaks/turbo issues → mixture control upset.
• Injector wear: worn nozzles/needles → over-fuelling, soot spike.
• Poor remaps: excessive injection duration (“no smoke no poke”) kills DPFs fast.
• Swirl flap failures and intake contamination accelerate soot build-up.

2) Diagnostic checklist (pre-work)

• Scan all modules, clear stored DTCs, and document live data.
• Attempt a forced regeneration to exit passive cycles before removal.
• Reset the DPF ash counter prior to flashing any MOD file.
• Confirm oil level/condition; verify pressure and temperature sensor health.
• Use OEM-grade diagnostics suitable for the platform.

3) ECU reading & file preparation

• OBD: read the original file; save SW/HW IDs.
• Bench/Boot: let CAN lines sleep, open ECU and read ORI safely.
• Upload ORI to TuningBot and request a DPF OFF calibration (with any required DTC handling).

4) Physical DPF processing (clean removal)

Remove the DPF assembly without damaging sensors/loom. Process the filter professionally and preserve a stock-like appearance.

• Unplug sensors and remove the DPF unit completely.
• Extract the core discreetly (do not cut a small window). SDS + chisel can help.
• Inspect pressure sensors and gaskets; weld back professionally.
• Check exhaust for leaks/corrosion; verify turbo condition while accessible.
• Re-install the unit carefully; do not start the vehicle yet.

5) Flashing the MOD file

• OBD: write the MOD file with a stable power supply.
• BDM/Bench: program, reseal ECU (board clean), reinstall, reconnect.

6) Final checks & road test

• Start engine and check for exhaust gas leaks.
• Idle 10–15 minutes, rescan for faults; then road-test to full temperature.
• Perform a final all-module diagnostic pass before delivery.

7) FAP/Additive systems reset (PSA and similar)

For additive-equipped systems (FAP), complete the resets with OEM diagnostics before flashing the MOD file.

1. Clear DTCs in ECU and BSI; ignition OFF, key out 3 min.
2. Resets: particulate data, pressure sensors, MAF data, EGR position; learn new catalyst if available; set additive tank replaced/refilled; ignition OFF 3 min.
3. Clean-up: clear residual DTCs; then flash the MOD file.
4. On some Peugeot HUD clusters, run the self-diagnostic to clear warnings.

8) Pro Tips & Best Practices

• Stable power supply — Regulated 12–14 V (≥50 A) during read/flash. Voltage drop = ECU corruption.
• EGT & thermostat — Cold-running engine or lazy EGT → wrong mixture control and soot rise.
• Pressure hoses — Check DPF differential hoses; reversed/clogged = false “soot mass”.
• Air-model consistency — After delete, verify MAF/MAP scaling; disable only regen-related maps.
• All regen triggers — Not just “DPF present”: timers, soot thresholds, post-injection requests.
• SCR/DOC handling — Keep non-DPF diagnostics active if the system remains installed.
• Turbo health — Shaft play/oil leaks will contaminate exhaust even without DPF.
• PCV / crankcase vent — Replace saturated separators; blow-by oil skews MAP and raises soot.
• Exhaust leak test — Smoke/pressure test after welding; tiny pre-sensor leaks skew readings.
• Reset learned values — Air/fuel adaptives after flash to avoid unstable idle/over-fuelling.
• Log & document — Idle, part-load, WOT logs; keep CSVs for traceability and support.
• QC checklist — No DTCs, diff-pressure ≈ 0 kPa at hot idle, EGT/ECT stable, smoke-free.

9) Quick FAQ

Is DPF delete a universal fix?

No. In most blocked-DPF cases the root cause is elsewhere (EGR/turbo/injectors). Diagnose and correct those first.

Do I need to reset the ash counter?

Yes. Skipping the ash-counter reset can keep the car in limp mode, prevent lamp clearing, or block DPF-related DTC gateways.

Any tip for the physical unit?

Remove the core cleanly and weld professionally; aim for a stock appearance and check sensors, seals, and leaks before start-up.