Powertrain, generic (extended)

P2A49 Alternative Fuel Tank C Pressure Sensor Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2A49 is the mirror image of P2A48: the tank C pressure signal sits above the band a healthy sensor uses, so the module rejects it. In TransEco's AFCM table the tank A equivalent traces back to a sensor with an open circuit or a short to the supply. An open ground is a classic trigger too, because the input is then pulled toward its supply rail. The practical danger is a cylinder that seems full when it is not; the gauge stays high and the system may count on gas from tank C until the engine starts to falter on a near-empty supply. No manufacturer lists P2A49 publicly. With the system depressurised and the plug off, check whether the voltage at the module side still reads high; if so, the fault lies in the harness rather than the sensor.

Likely causes

Ground or signal wire of the tank C sensor interrupted
Signal shorted to 5 V or battery voltage
Tank C sensor open internally

Symptoms

  • Check engine light
  • Gauge for tank C stays at full
  • Hesitation once tank C really runs low

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

P2A46P2A48P2A4AP2A44P01A1

References: law.cornell.edu, http:.