Powertrain, generic · Auxiliary emission controls

P048C Exhaust Pressure Control Valve A Position Sensor/Switch Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

An exhaust pressure control valve is an electrically driven flap in the exhaust with a position sensor or end-position switch, usually inside the actuator. Valve A is the first such flap; Bentley's V8 assigns A to bank 1 and B to bank 2. Documented uses are the flap behind the particulate filter of VW's and Audi's 2.0 TDI, which raises back pressure for the low-pressure EGR, and the sound flaps of Audi and Bentley. P048C means valve A's position signal is electrically valid but does not match the commanded position or the learned end positions. It is documented only on VW's and Audi's 2.0 TDI of 2009–13, together with P047F, P048A, P048B and P0401, caused by the corroded, sticking flap shaft. After replacing the actuator, the end positions must be relearned.

Likely causes

Flap or shaft corroded or coked (stiff)
End positions not relearned after replacement
Position sensor in the actuator drifting
Contact resistance in the connector

Symptoms

  • Check engine light on
  • Flap without function, exhaust sound changed
  • VW/Audi TDI: EGR fault P0401 possible

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€150–1,200
Time0.5–2.5 h

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

Parts involved

exhaust pressure control valve a position sensorexhaust pressure control valve asensor wiringengine control module

Related codes

P048BP048DP048EP048AP047FP04A7

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