Powertrain, generic (extended)

P24FA Exhaust Aftertreatment Fuel Air Purge Valve Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P24FA reports that voltage on the purge valve control line is lower than the driver stage expects in the current switching state: a short to ground on the wire, a coil with too little resistance or a weak supply. Volvo and Mack name P24FA00 in the electrical section of their AHI troubleshooting guide for US10+OBD13 and newer engines; the work there is on the dosing module plug and the harness, not on the air or fuel side. Depending on how the driver is wired, a ground short can either keep the valve energised permanently or stop it from switching. In both cases the purge cycle after hydrocarbon dosing becomes unreliable, and the controller may suspend active regeneration until the fault is fixed. An open circuit is P24F8, the opposite polarity P24FB.

Likely causes

Control wire chafed through to chassis ground
Purge valve coil with shorted turns
Moisture in the AHI module connector

Symptoms

  • Warning lamp shortly after key-on or during dosing
  • Regeneration not possible

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–1,200
Time0.5–3 h

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

Parts involved

aftertreatment purge valvesolenoid driver

Related codes

P24F8P24F9P24FB

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