Powertrain, generic (extended)

P24FB Exhaust Aftertreatment Fuel Air Purge Valve Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

With P24FB the purge valve control line sits higher than allowed, a pattern that points to a short to battery voltage or to a broken low-side path, so the controller cannot pull the line down. In the Volvo/Mack AHI guide P24FB00 is listed right beside P24FA00 among the electrical codes, and the first check is the harness and the plug at the dosing module. If the valve never energises, compressed air does not flush the feed to the 7th injector, and fuel left there can carbonise over time. A driver stage that shuts itself off against overcurrent may also log this code. The low counterpart is P24FA, a plain interruption P24F8. Expect a warning lamp and, on trucks, a dash message about filter regeneration.

Likely causes

Control wire shorted to a battery-voltage feed in the harness
Interrupted return path between valve and controller
Controller output stage protecting itself against overcurrent

Symptoms

  • Warning lamp and aftertreatment message
  • Filter regeneration unavailable

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

P24F8P24F9P24FA

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