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DTC codes / P0Exx · Hybrid propulsion / P0E5A

P0E5ADC/DC Converter Temperature Sensor C Circuit Low

P0E5A indicates that the powertrain control module has detected a low voltage signal from the temperature sensor circuit for the DC/DC converter, specifically on sensor C. The DC/DC converter changes high-voltage battery power to the low voltage needed for accessories, and this sensor monitors its internal temperature to prevent overheating.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaHybrid propulsion

Symptoms you may notice

  • Illumination of the check engine light or service vehicle soon message
  • Often no symptoms besides the warning light
  • Reduced power or limp mode if the converter derates due to high temperature
  • Intermittent charging system warnings or low voltage accessories
  • Possible overheating smell or hot converter housing in severe cases
  • Loss of certain electrical functions if the converter shuts down

Common causes, most likely first

  1. Faulty temperature sensor C inside the DC/DC converter
  2. Damaged or corroded wiring harness or connector at the converter
  3. Open or short circuit in the sensor signal circuit
  4. Poor ground connection for the converter or sensor
  5. Failed DC/DC converter assembly (internal sensor or circuit board fault)
  6. Corrosion or water intrusion into the converter housing
  7. Software glitch in the control module (rare)

How to diagnose and fix it

  1. Use a scan tool to verify the code and check live temperature sensor data for sensor C
  2. Inspect the wiring harness and connectors at the DC/DC converter for damage, corrosion, or loose pins
  3. Measure resistance and voltage on the sensor signal circuit to check for opens or shorts
  4. Check the converter's ground connections and repair any high resistance
  5. If wiring is good, test the sensor itself with a multimeter and compare to specifications
  6. Replace the DC/DC converter assembly if the sensor is internal and faulty
  7. Clear the code and perform a road test to confirm the repair

Don't replace the converter before checking this

  • A low signal from temperature sensor C often results from a poor ground connection rather than a failed sensor, so always verify ground integrity first.
  • The DC/DC converter may share its ground with other high-voltage components, and a single corroded ground point can set this code without any converter fault.
  • Some vehicles use multiple temperature sensors inside the converter, and sensor C may be a redundant or secondary sensor that only triggers a code under specific load conditions.
  • After replacing the converter, the new unit may require programming or adaptation with a scan tool to recognize the new sensor, otherwise the code may persist.
  • This code can be set by a temporary overheating event, so check for blocked cooling ducts or fan failures before condemning the converter.

Can I keep driving with P0E5A?

You can usually drive with this code, but avoid heavy electrical loads and long trips until it is diagnosed, because a failing converter could eventually stop charging the 12-volt system and leave you stranded.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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