Powertrain, generic (extended)

P2CA5 DC/DC Converter Temperature Sensor E Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2CA5 is the general circuit fault of the fifth temperature sensor in a DC/DC converter, the one carrying letter E. Converters measure several hot spots because each part heats differently: a Hyundai patent for a hybrid high-side converter places separate sensors on the inductor and on both IGBT switches, high side and low side, and changes the switching frequency when their readings drift apart. No manufacturer documents P2CA5 publicly; the highest letter found in a bulletin is sensor D on the 2021 Ram 1500 eTorque (FCA 08-037-21). The code fits a signal that is unusable but cannot be classed as low, high or implausible. CARB requires circuit checks for such hybrid inputs. Expect the converter to be derated, which can strain the 12 V battery.

Likely causes

Loose, corroded or pushed-out terminal at the converter connector
Temperature sensor E inside the converter failed
Evaluation circuit of the converter control board faulty

Symptoms

  • Hybrid or electrical system warning and MIL on
  • DC/DC converter output limited, 12 V battery discharges

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 ewiring harnessdcdc converter

Related codes

P2CA6P2CA7P2CA8P2CA9P2C8CP0E58

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