Faulty input voltage sensor C on the battery charger assembly; Damaged or corroded wiring in the sensor circuit, including open or short circuits; Loose or contaminated connector pins at the sensor or control module; Water intrusion or physical damage to the charger assembly affecting the sensor; Internal failure within the battery charger module causing incorrect sensor readings; Software glitch or outdated calibration in the control module

DTC codes / P0Exx · Hybrid propulsion / P0EFC

P0EFCBattery Charger A Input Voltage Sensor C Circuit

Q: What does code P0EFC mean?

Battery Charger A Input Voltage Sensor C Circuit. P0EFC indicates that the powertrain control module has detected an abnormal voltage signal on the input voltage sensor C circuit of battery charger A, which is typically part of the high-voltage charging system in electrified vehicles. The computer compares the sensor's reported voltage against expected values and flags the circuit when the signal falls outside the valid range or is inconsistent with other voltage measurements.

P0EFC indicates that the powertrain control module has detected an abnormal voltage signal on the input voltage sensor C circuit of battery charger A, which is typically part of the high-voltage charging system in electrified vehicles. The computer compares the sensor's reported voltage against expected values and flags the circuit when the signal falls outside the valid range or is inconsistent with other voltage measurements.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaHybrid propulsion

Symptoms you may notice

Illumination of the check engine light or service vehicle soon message
Often no symptoms besides the warning light, especially if the fault is intermittent
Reduced or disabled high-voltage charging, leading to longer charge times or inability to charge
Powertrain power reduction or limp mode in some vehicles
Audible alerts or charging system warning messages on the dashboard

Common causes, most likely first

Faulty input voltage sensor C on the battery charger assembly
Damaged or corroded wiring in the sensor circuit, including open or short circuits
Loose or contaminated connector pins at the sensor or control module
Water intrusion or physical damage to the charger assembly affecting the sensor
Internal failure within the battery charger module causing incorrect sensor readings
Software glitch or outdated calibration in the control module

How to diagnose and fix it

Connect a scan tool and record all stored codes and freeze-frame data to understand the fault context
Visually inspect the battery charger assembly and sensor circuit wiring for damage, corrosion, or loose connections
Measure resistance and voltage on the sensor C circuit to check for opens, shorts, or excessive resistance
Compare sensor live data against actual measured voltages using a multimeter to verify sensor accuracy
Check for technical service bulletins or software updates for the vehicle's charging system
Replace the faulty input voltage sensor or charger assembly if testing confirms an internal failure
Clear codes and perform a road test or charging cycle to verify the repair and ensure the code does not return

Before you replace the charger assembly

A common oversight is assuming the charger assembly is defective when the real problem is a chafed wire harness near a sharp bracket or heat source, so always perform a thorough circuit integrity test first.
Intermittent codes often stem from connector fretting corrosion, which can be resolved by cleaning and applying dielectric grease rather than replacing expensive components.
The input voltage sensor C circuit may share a reference voltage with other sensors, so a fault in a related circuit can trigger P0EFC as a secondary code.
Some vehicles require a calibration or relearn procedure after sensor replacement, and skipping this step can cause the code to reset immediately.
High-voltage system faults can be misdiagnosed as sensor issues when the actual problem lies in the charger's internal power electronics, so follow the manufacturer's diagnostic flow chart carefully.

Can I keep driving with P0EFC?

If the vehicle drives normally and only the warning light is on, you can continue driving short distances, but avoid relying on high-voltage charging until the fault is repaired. If the vehicle enters limp mode or charging is completely disabled, arrange for professional diagnosis and repair before driving further.

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.