Powertrain, generic (extended)

P24E0 Reductant Purge Control Valve B Stuck Closed

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

Stuck closed means purge valve B does not move into its emptying position when commanded after shut-down, so the line it serves stays filled with fluid under residual pressure. In normal dosing this goes unnoticed; the risk appears in frost, when the trapped DEF freezes in hose, pump or injector and can crack them. No manufacturer documents P24E0 publicly. How a blocked valve A is detected on GM's Duramax diesel: the pressure drop during the purge phase is measured, and less than 50 kPa sets P20A1, Type A. Pico's Denoxtronic 2.2 description shows that the purge relies on the reversing valve and the closed injector to create vacuum. CARB demands monitoring of SCR components. P24DF is the reverse failure.

Likely causes

Valve B seized by crystallised DEF or corrosion
Weak coil that no longer pulls the valve over
Intermittent open in the control circuit during shut-down

Symptoms

  • Malfunction indicator lamp on
  • Frozen or burst DEF line or injector after frost

Repair estimate

DifficultyHardWorkshop job
Parts and labour€300–1,500
Time1–4 h

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

Parts involved

reductant purge valve b

Related codes

P24DFP24DCP20A5

References: gsi.ext.gm.com, picoauto.com, law.cornell.edu.