A faulty DC/DC converter voltage sensor that reports a higher voltage than actually present; Damaged or chafed wiring in the sensor signal circuit, including a short to voltage; Corroded, loose, or backed-out terminals at the converter, sensor, or control module connectors; An internal fault in the DC/DC converter causing genuinely high output voltage; A poor ground connection shared by the converter or sensor, skewing the signal reference; A software or calibration issue in the control module that misinterprets the sensor signal; A failed control module driver circuit for the sensor reference or signal return

DTC codes / P0Exx · Hybrid propulsion / P0E39

P0E39DC/DC Converter Voltage Sensor B High

Q: What does code P0E39 mean?

DC/DC Converter Voltage Sensor B High. P0E39 means the powertrain control module has detected an abnormally high voltage signal from the sensor that monitors the output of a direct current to direct current (DC/DC) converter, which is the component that steps one DC voltage level up or down to another. The computer compares this signal against expected limits and sets the code when the reported voltage stays above the calibrated threshold for a set time.

P0E39 means the powertrain control module has detected an abnormally high voltage signal from the sensor that monitors the output of a direct current to direct current (DC/DC) converter, which is the component that steps one DC voltage level up or down to another. The computer compares this signal against expected limits and sets the code when the reported voltage stays above the calibrated threshold for a set time.

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 with no other noticeable symptoms
Reduced or absent output from the DC/DC converter, which may leave a low-voltage system undercharged
Electrical accessories such as lighting, infotainment, or power outlets behaving erratically or shutting down
A battery warning light or charging system message appearing alongside the check engine light
The vehicle entering a reduced-power or failsafe mode that limits certain electrical functions
Intermittent electrical faults that appear and disappear with temperature or vibration

Common causes, most likely first

A faulty DC/DC converter voltage sensor that reports a higher voltage than actually present
Damaged or chafed wiring in the sensor signal circuit, including a short to voltage
Corroded, loose, or backed-out terminals at the converter, sensor, or control module connectors
An internal fault in the DC/DC converter causing genuinely high output voltage
A poor ground connection shared by the converter or sensor, skewing the signal reference
A software or calibration issue in the control module that misinterprets the sensor signal
A failed control module driver circuit for the sensor reference or signal return

How to diagnose and fix it

Scan all modules for stored and pending codes, then record freeze-frame data for P0E39 before clearing anything
Inspect the DC/DC converter, its voltage sensor, and all related connectors for corrosion, looseness, or damage
Measure the actual converter output voltage with a digital multimeter and compare it to the sensor-reported value
Back-probe the sensor signal circuit and check for a short to voltage or an open circuit while wiggling the harness
Verify the sensor ground and reference voltage at the connector match the manufacturer's specification
If the signal circuit and grounds test good, substitute a known-good sensor or converter only after confirming the fault follows the part
After repair, clear codes and run the vehicle through the manufacturer's monitor readiness procedure to confirm the code does not return

What the converter sensor signal really tells you

A high sensor signal often comes from a short to voltage in the harness rather than a failed converter, so always check the signal wire for contact with a power circuit before condemning the part.
The DC/DC converter voltage sensor may be integrated into the converter assembly on some vehicles, meaning a sensor fault can require converter replacement, while on others it is a separate serviceable component.
A weak or failing 12-volt battery can cause erratic converter operation and set this code indirectly, so load-test the battery and charging system before deeper diagnosis.
This code can be stored by a control module that has lost its ground reference, causing the sensor signal to float high even though the converter is working correctly.
After any repair, the code may remain stored until the converter monitor runs under specific conditions, so a short test drive may not be enough to confirm the fix.

Can I keep driving with P0E39?

The vehicle is usually safe to drive short distances to a repair shop, but avoid relying on electrical accessories and do not tow heavy loads or drive at length if the charging system warning is also present. If the vehicle enters a reduced-power mode or the battery voltage drops, stop driving and arrange a tow.

Tools that help

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