Powertrain, generic (extended)

P2A46 Alternative Fuel Tank C Pressure Sensor Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

Larger CNG installations, for instance on trucks or buses, may carry three or more cylinders. Where a third one, tank C, has its own pressure transducer, P2A46 reports a general electrical fault in that sensor's circuit, stored when the module finds the signal unusable but cannot classify it as too low or too high. Publicly described is only the single tank sensor of simpler systems: Ford placed it inside the regulator of its 2003 bi-fuel CNG pickups and let the AFCM derive the gauge reading from it. No manufacturer lists P2A46. In practice the first checks are the three wires at the tank C sensor, the connector seal and the shared 5 V feed; the narrower codes P2A48 and P2A49 name a low or high signal, P2A4A short interruptions.

Likely causes

Wiring or plug at the tank C sensor damaged, loose or wet
Tank C pressure sensor faulty
Shared 5 V supply or sensor ground disturbed

Symptoms

  • Check engine light
  • Remaining gas shown wrongly
  • Tank C may be left unused

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 c pressure sensorwiring harnessafcm

Related codes

P2A47P2A48P2A49P2A4AP2A41P019E

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