P0EFB flags an electrical fault on the third AC input voltage channel of on-board charger A, sensor C. Channel A reports through P0D3D to P0D41, channel B through P0EF7 to P0EFA; a third channel fits chargers that read each phase of a three-phase supply separately. This is the catch-all circuit code, used when the signal is unusable without being sorted into range, low or high (P0EFC, P0EFD, P0EFE). No manufacturer documents P0EFB publicly, and GM's hybrid tables for 2011, 2012 and 2014 to 2019 never list the matching circuit code P0D3D either, catching wiring faults on sensor A only through its low and high checks. In TI's 11 kW reference design every phase is scaled by a resistor chain and centred at 1.65 V in a 3.3 V converter, so a dead channel is easy to spot. AC charging is refused or limited.
High severity. Can I keep driving?If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.
Symptoms
- AC charging does not start or is limited
- Possible reduced charging power on three-phase stations
- Charging fault shown in the cluster or app
Most likely causes
- Failed measuring channel C on the charger board (divider, amplifier or converter input)
- Open or loose sense connection for this phase inside the charger or at the AC inlet harness
- Charger software marking a valid channel as faulty
What to check, in order
Start with the simplest. You can tick off each step.
What each character of P0EFB means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- E: Subsystem depends on the code range
- FB: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0EFB?
If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.
What causes code P0EFB?
The most common causes are: failed measuring channel C on the charger board (divider, amplifier or converter input); open or loose sense connection for this phase inside the charger or at the AC inlet harness; charger software marking a valid channel as faulty.
Related codes
- P0EFCBattery Charger A Input Voltage Sensor C Circuit Range/Performance
- P0EFDBattery Charger A Input Voltage Sensor C Circuit Low
- P0EFEBattery Charger A Input Voltage Sensor C Circuit High
- P0EF7Battery Charger A Input Voltage Sensor B Circuit
- P0D3DBattery Charger A Input Voltage Sensor A Circuit
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.