Powertrain, generic

P0E31 DC/DC Converter Voltage Sensor A Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P0E31 is the general circuit code of voltage sensor A in a DC/DC converter, the measurement the converter or its controller uses to regulate output voltage. It is used for electrical faults that do not fit the low, high or erratic categories. P0E31 itself is not documented publicly by any manufacturer. GM's 2025 engine tables use the neighbouring codes for the same sensor in a converter that steadies the 12 V supply during engine auto-starts: P0E33 below 1 V, P0E34 above 28 V, P0E32 for implausible values. FCA names sensor A as voltage sensor 1 on the 2021 Ram 1500 eTorque. CARB wants open circuits and out-of-range signals of such inputs reported separately where feasible. With a lost voltage signal the converter tends to stop or run in a fallback mode.

Likely causes

Voltage measurement inside the DC/DC converter failed
Wiring or connector fault on the converter
Poor ground connection of the converter

Symptoms

  • Warning light and possibly 12 V battery warning
  • Engine auto-stop disabled or reduced 12 V supply

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–1,500
Time0.5–3 h

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

Parts involved

dcdc voltage sensor awiring harnessdcdc converter

Related codes

P0E32P0E33P0E34P0E35P0E36

References: law.cornell.edu, gsi.ext.gm.com, static.nhtsa.gov.