Powertrain, generic (extended)

P2A53 Alternative Fuel Vaporizer A Outlet Temperature Sensor Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2A53 is the opposite case: the voltage of the vaporizer A outlet sensor sits near the supply reference, which a thermistor input reads as extreme cold. A broken wire, an unplugged or corroded connector, an open sensor element or a short to a voltage source all produce this. AC STAG names the open variant a missing reducer temperature sensor. Because its controllers only change over to gas once the reducer temperature allows it, such a reading keeps a bi-fuel vehicle on petrol; a dedicated gas engine may refuse to start or run with reduced output. TransEco handles the related rail sensor High code the same way, forcing petrol mode with the lamp on. No manufacturer publishes P2A53 itself. Bridging the plug pins should make the value jump to very hot.

Likely causes

Wire broken or connector unplugged
Sensor element open inside
Signal wire shorted to a voltage source

Symptoms

  • Check engine light, depending on calibration
  • No switch-over to gas, bi-fuel vehicle stays on petrol
  • Live data shows a vaporizer far below freezing

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–450
Time0.5–2 h

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

Parts involved

alt fuel vaporizer a outlet temp sensorwiring harnessafcm

Related codes

P2A50P2A51P2A52P2A54P2A58

References: law.cornell.edu, mystag.pl, http:.