Fix Library /

DPF / EGR problems

Loss of power, regen issues, soot codes. Don’t ‘delete’ — diagnose driving pattern, sensors, and soot load first.

MED RISK

Common symptoms

  • Limp mode
  • Poor mpg
  • Frequent regens
  • DPF/EGR warning light

Cost expectations

DIY: £20–£80 (additive/cleaners). Garage: £150–£900 depending on soot load.

Note: prices vary by car and region. Use this as a planning range.

Most likely causes (ranked)

  1. Short journeys — No full regen cycles.
  2. Sensor issues — DPF pressure sensor, temp sensors.
  3. EGR sticking — Poor combustion and soot buildup.
  4. Boost/air issues — Underboost increases soot.
  5. High soot load — Needs forced regen or removal cleaning.

Quick checks (fast, low-cost)

  • Scan soot load/DPF differential pressure if available.
  • Check for boost leaks/underboost codes first.
  • Verify sensors readings (pressure/temp) are plausible.
  • Inspect EGR for sticking (platform dependent).
  • Use proper DPF cleaner only if soot load isn’t extreme.

Recommended tools

These tools make diagnosis faster and stop you buying random parts.

Related fixes

If your symptoms don’t match perfectly, check these next.

Limp modeUnderboostBlack smoke

What to do next

  • Fix underlying air/boost issues first.
  • Avoid repeated short trips; do a proper regen drive where safe.
  • If soot load is high, get professional cleaning.

AutoSolveHub helps you narrow possibilities. Always confirm critical repairs with proper testing and safe procedures.