Powertrain, generic

P0E98 DC/DC Converter Voltage Sensor C Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P0E98 is set when the C voltage channel of a DC/DC converter is stuck at the lowest end of its range, typically because the measuring line is grounded or the sensing stage has lost its supply. No manufacturer documents P0E98 publicly. GM's 2025 tables (25OBDG03A) show the matching test on channels A and B of the 12 V stabiliser used for auto-starts: below 1 V in 320 out of 400 readings at a 12.5 ms rate gives P0E33 or P0E38, rated Type B. A third channel would be judged the same way. CARB calls for range monitoring of inputs like this. If the converter output itself is normal on the other channels, the fault lies in the C path. The high counterpart is P0E99.

Likely causes

Sensor C signal line shorted to ground
Measuring stage without supply or with an open signal path
Internal defect in the converter's measuring circuit

Symptoms

  • MIL on, depending on the manufacturer's rating
  • Converter output reduced or switched to a fallback value
  • Start-stop or 12 V support may be disabled

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 cwiring harnessdcdc converter

Related codes

P0E99P0E96P0E97P0E9AP0E33P0E38

References: law.cornell.edu, gsi.ext.gm.com.