Powertrain, generic (extended)

P2A99 Alternative Fuel Tank Select Valve C Control Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2A99 belongs to installations with at least three selectable vessels or supplies and reports an open or otherwise broken control circuit at select valve C. Published designs mostly show two vessels, such as Westport's LNG arrangement with one pump and a valve choosing the tank, or Cespira's pair of compressed-gas supplies; a third valve extends the same principle. With valve C unpowered, its vessel can neither be brought on line nor, depending on the rest position, taken off line, so the selection sequence breaks at that point. Take care not to confuse it with P2A26, the shutoff solenoid on tank C, or with the hydraulic pump select valve. No manufacturer documents P2A99. Check the plug, the lead and the coil of valve C.

Likely causes

Disconnected plug or broken lead at select valve C
Coil of valve C burnt out
Module output for valve C failed

Symptoms

  • Malfunction lamp on
  • Third vessel stays full or is never isolated
  • Total range reduced

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,200
Time1–4 h

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

Parts involved

alt fuel tank select valve cwiring harnessafcm

Related codes

P2A9AP2A9BP2A9CP2A91P2A95P2A26

References: law.cornell.edu, patents.google.com, patents.google.com.