Powertrain, generic (extended)

P224F Alternative Fuel Tank Shutoff Valve A Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P224F reports a control circuit of tank shutoff valve A that reads too high, typically a wire touching battery voltage. In TransEco Energy's AFCM fault list the cause is given as shorted to power, the MIL is lit and the gas system keeps working under the failure mode strategy. That matters because a valve held open by an external voltage can no longer be closed by the control unit: Ford's 2003 bi-fuel CNG system relies on closing the tank valve when gas pressure falls below 517 kPa, and GM's bi-fuel Impala keeps its cut-off solenoids energized only while the engine turns. Ford's Boss 302S list carries P224F too, though mislabelled as Low. P224E is the low side; CARB requires both directions to be monitored.

Likely causes

Control wire of the tank valve shorted to battery voltage
Output stage in the alternative fuel control module stuck on
Wiring mistake after a conversion or repair

Symptoms

  • Check engine light
  • Tank valve may stay open after switching off

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–900
Time0.5–3 h

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

Parts involved

alternative fuel shutoff valve

Related codes

P224CP224DP224EP2A25

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