A loose, corroded, or backed-out terminal in the current sensor connector or the converter harness; Chafed or intermittently shorted wiring between the current sensor and the control module, often near a heat source or vibration point; A failing current sensor internal to the DC/DC converter assembly that loses signal only when hot or under load; Poor ground connection for the converter or sensor reference circuit causing the signal to float; Water intrusion or contamination in the converter housing or connector causing intermittent conductivity; A software calibration issue in the control module that misinterprets a normal signal during certain load transitions; A failing DC/DC converter that draws abnormal current and pushes the sensor signal outside its expected range intermittently

DTC codes / P0Exx · Hybrid propulsion / P0E55

P0E55DC/DC Converter Current Sensor A Circuit Intermittent/Erratic

P0E55 indicates that the powertrain control module has detected an intermittent or erratic signal from the current sensor circuit that monitors the DC/DC converter, which is the component that steps high-voltage battery power down to charge the 12-volt system. The computer is not reporting a hard failure but rather a signal that drops out, spikes, or becomes inconsistent beyond what the software considers normal for the operating conditions.

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
Intermittent charging system warning light or a voltmeter that fluctuates without a clear pattern
Accessories such as interior lights or infotainment flickering or dimming briefly during driving
A 12-volt battery that slowly discharges or requires frequent jump starts despite a healthy battery
Reduced power or limp-home mode in some vehicles when the fault escalates from intermittent to continuous
No drivability change at all in many cases because the converter continues to operate while only the feedback signal is erratic

Common causes, most likely first

A loose, corroded, or backed-out terminal in the current sensor connector or the converter harness
Chafed or intermittently shorted wiring between the current sensor and the control module, often near a heat source or vibration point
A failing current sensor internal to the DC/DC converter assembly that loses signal only when hot or under load
Poor ground connection for the converter or sensor reference circuit causing the signal to float
Water intrusion or contamination in the converter housing or connector causing intermittent conductivity
A software calibration issue in the control module that misinterprets a normal signal during certain load transitions
A failing DC/DC converter that draws abnormal current and pushes the sensor signal outside its expected range intermittently

How to diagnose and fix it

Inspect the current sensor connector and converter harness for loose pins, corrosion, or chafing, and perform a wiggle test while watching live data
Check the sensor reference voltage and ground at the connector with a multimeter to confirm the circuit is stable under vibration
Monitor the current sensor parameter on a scan tool during a road test to catch the erratic signal and correlate it with load or temperature
Verify the 12-volt charging output of the DC/DC converter with a meter to see whether the erratic signal corresponds to an actual charging fault
Check for technical service bulletins or calibration updates for the control module that address intermittent current sensor reporting
Replace the current sensor or converter assembly only after circuit and ground integrity are confirmed, then clear codes and re-test
Perform a final road test with live data to confirm the signal remains stable across all operating conditions before returning the vehicle

What the intermittent signal really tells you

An intermittent current sensor code often appears only after the converter has been under sustained load, so a cold idle test will frequently show nothing wrong and lead to a premature no-fault conclusion.
The current sensor is frequently integrated into the DC/DC converter assembly, meaning a sensor fault can force replacement of a converter that is still functioning perfectly, so circuit testing must come first.
A weak or aging 12-volt battery can cause the converter to operate at higher current for longer periods, which stresses the sensor circuit and can trigger this code without any fault in the sensor itself.
Water intrusion into the converter connector is a commonly overlooked cause on vehicles with underbody-mounted converters, and the corrosion often hides behind the connector seal where a visual check misses it.
This code does not always mean the converter has failed; the control module can set it from a single erratic sample during a voltage transient, so clearing the code and monitoring for recurrence is a valid first step after circuit inspection.

Can I keep driving with P0E55?

The vehicle is generally safe to drive while the fault remains intermittent, but avoid long trips or heavy electrical loads until the circuit is inspected because a failing converter can eventually stop charging the 12-volt battery. If the charging warning light comes on steadily or the battery voltage drops, stop driving and arrange service.

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.