Powertrain, generic (extended)

P2A41 Alternative Fuel Tank B Pressure Sensor Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

Some multi-tank CNG installations give a second cylinder, tank B, its own pressure transducer, so the module knows the remaining gas per tank and can check that the tank valve responds. P2A41 is the general electrical fault of that sensor, set when the circuit is faulty without a clear verdict of low or high. Publications only describe the single sensor of tank A: on Ford's 2003 bi-fuel CNG trucks it is built into the regulator and drives the gauge, which the AFCM forces to empty when the sensor fails. The upfitter TransEco substitutes a fixed 3600 psi and keeps running. No manufacturer lists P2A41. Check the 5 V feed, signal and ground at the tank B sensor plug first; P2A43 and P2A44 separate the low and high cases, P2A45 brief dropouts.

Likely causes

Plug at the tank B sensor loose, corroded or harness damaged
Tank B pressure sensor faulty
5 V reference or sensor ground disturbed

Symptoms

  • Check engine light
  • Gas gauge wrong or showing empty
  • Tank B possibly no longer used

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–700
Time1–3 h

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

Parts involved

alt fuel tank b pressure sensorwiring harnessafcm

Related codes

P2A42P2A43P2A44P2A45P019E

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