Powertrain, generic (extended)

P24F9 Exhaust Aftertreatment Fuel Air Purge Valve Control Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P24F9 covers a purge valve control circuit that is electrically present but behaves implausibly, for example when measured current or a feedback signal does not follow the commanded state within the expected time. Unlike P24F8, P24FA and P24FB, this variant appears in none of the Volvo/Mack AHI documents, and no manufacturer documents P24F9 publicly. The part involved is the same: a solenoid in the dosing module that admits compressed air to flush fuel out of the line to the exhaust injector after each dosing event. CARB's heavy-duty rule 1971.1 obliges systems that blow fuel into the exhaust with air assistance to detect any failure that leaves the filter unable to regenerate. Plausible triggers are a sluggish valve, drifting coil resistance or a high-resistance contact.

Likely causes

Purge valve moving slowly because of deposits
Solenoid coil resistance drifting with heat or age
High-resistance contact in the module plug

Symptoms

  • Warning lamp, sometimes only under heat
  • Irregular or aborted filter regenerations

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€150–1,200
Time0.5–3 h

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

Parts involved

aftertreatment purge valve

Related codes

P24F8P24FAP24FBP24F7

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