Powertrain, generic (extended)

P224C Alternative Fuel Tank Shutoff Valve A Control Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P224C points to an open or otherwise faulty control circuit of shutoff valve A, the solenoid on a CNG or LPG tank that releases gas only when the engine runs on the alternative fuel. Such valves are normally closed. GM's 2015 bi-fuel Impala (bulletin PI1330) fits a high-pressure cut-off solenoid to the tank and energizes it in CNG mode while the engine cranks or runs; Ford's 2003 bi-fuel CNG documentation feeds its tank valve through the inertia switch and the ALT fuel relay. Neither publishes codes for the valve. No maker documents P224C publicly, and the CNG upfitter TransEco even files an open circuit under P224E. With the valve dead, bi-fuel cars carry on with gasoline; dedicated gas vehicles may not start.

Likely causes

Broken wire or unplugged connector at the tank valve
Solenoid coil of the valve open
Supply interrupted by relay or tripped inertia switch

Symptoms

  • Check engine light
  • Vehicle will not switch to gas operation or falls back to gasoline

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

P224DP224EP224FP2A22

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