Powertrain, generic · Auxiliary emission controls

P047F Exhaust Pressure Control Valve A Stuck Open

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

The exhaust pressure control valve is a flap in the exhaust: on older Navistar/Ford diesels a warm-up flap that raises back pressure when cold, on Ram and others an exhaust brake, on VW's 2.0 TDI a flap that drives the low-pressure EGR, and on Audi and Bentley a sound flap. P047F means valve A stays open although it is commanded to close, detected by the flap's position sensor or by missing back pressure. On VW's 2.0 TDI and Audi's A3 TDI of 2009–12 the code appears with P0477, P048A–P048C and P0401: water and road salt corrode the flap shaft so the flap sticks; improved parts were introduced. As the flap drives the low-pressure EGR there, EGR flow is then too low.

Likely causes

Flap shaft corroded or seized
Soot or carbon on the flap
Actuator or linkage faulty or unhooked
Position sensor reports wrongly

Symptoms

  • Check engine light on
  • EGR flow too low (P0401), higher NOx
  • Exhaust brake or warm-up flap without effect, possibly louder exhaust

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€150–1,000
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

exhaust pressure control valve avalve actuatoractuator wiringengine control module

Related codes

P048AP0476P0477P048BP0401P04A4

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov, law.cornell.edu.