P2A5C Alternative Fuel Vaporizer C Outlet Temperature Sensor Circuit Low

P2A5C stands for a vaporizer C outlet signal below the valid range. Since such inputs are normally NTC thermistors, the module would read an implausibly hot unit; a signal lead touching ground or a sensor shorted internally is far more likely. Coolant that has seeped into the connector can also create a path to ground. AC STAG controllers show this as a short in the reducer temperature circuit and advise checking insulation and plug. A wrongly hot vaporizer C is a safety concern, since gas could pass through a unit that is in fact too cold to vaporize it fully. No manufacturer documents P2A5C. Disconnect the sensor and watch the value: a jump to cold means the sensor itself is shorted, no change means the fault sits in the wiring.

Likely causes

Symptoms

• Check engine light, depending on calibration
• Gas operation blocked or limited
• Vaporizer C shown far too hot

Repair estimate

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

Parts involved

Related codes

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