Powertrain, generic (extended)

P2CA9 DC/DC Converter Temperature Sensor F Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2CA9 is the general fault code for the circuit of the sixth DC/DC converter temperature sensor, letter F. Which component this sensor watches is left to the manufacturer. No manufacturer documents P2CA9 publicly; the converter sensors visible in bulletins end at D (Ram 1500 eTorque, FCA 08-037-21). Why a converter has several measuring points is shown by a Hyundai patent: inductor and both IGBTs are measured separately so that the controller can balance how hot they get. The code serves for input faults that cannot be sorted into low, high or implausible. CARB demands circuit monitoring of hybrid inputs. A derated converter can gradually drain the 12 V battery; sensor E's general circuit code is P2CA5.

Likely causes

Damaged harness or poor contact in the sensor F circuit
Temperature sensor F inside the converter failed
Input stage on the converter control board faulty

Symptoms

  • MIL and hybrid system warning on
  • Converter output limited, 12 V voltage may sag

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–2,500
Time0.5–5 h

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

Parts involved

dcdc converter temp sensor fwiring harnessdcdc converter

Related codes

P2CAAP2CABP2CACP2CA5P2C8CP0E58

References: law.cornell.edu, patents.google.com, static.nhtsa.gov.