Powertrain, generic (extended)

P2C8C DC/DC Converter Temperature Sensor D Circuit

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P2C8C reports a general fault in the circuit of the fourth temperature sensor of a DC/DC converter, after sensors A, B and C (P0C38, P0C3D, P0E58). Where sensor D sits inside the converter is up to each maker. That such a fourth sensor exists in practice is shown by FCA: the 2021 Ram 1500 with the 3.6 L eTorque mild hybrid watches converter sensors 1, 2, C and D, yet bulletin 08-037-21 lists only the plausibility code P2C8D for sensor D. No manufacturer documents P2C8C publicly. The code fits a signal the controller recognises as unusable but cannot sort into too low, too high or implausible. CARB requires circuit checks on hybrid input components. Without this reading the controller normally reduces converter output, which can weaken support for the 12 V system.

Likely causes

Sensor connector or wiring damaged or corroded

Temperature sensor D in the converter defective

Sensor reference or evaluation circuit inside the converter faulty

Symptoms

MIL or hybrid system warning
Converter output limited, 12 V charging voltage may drop

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 dwiring harnessdcdc converter

References: law.cornell.edu, static.nhtsa.gov.