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DTC codes / P0Cxx · Hybrid propulsion / P0CFB

P0CFBControl Pilot Charging Switch A Circuit High

P0CFB indicates that the powertrain control module has detected an abnormally high voltage on the control pilot charging switch A circuit, which is part of the electric vehicle charging system. The computer expects a specific voltage range on this circuit when the switch is open or closed, and a high reading means the circuit is shorted to voltage or the switch is stuck in a state that keeps the signal high.

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

Symptoms you may notice

  • The charging system warning light or service vehicle soon light illuminates on the dashboard.
  • The vehicle may refuse to start charging when plugged in, or charging may stop unexpectedly.
  • A message may appear on the driver information display indicating a charging system fault.
  • Often no symptoms besides the warning light, especially if the fault is intermittent.
  • The charging port door may not latch or release properly if the switch is mechanically stuck.
  • In some cases, the vehicle may not recognize the charging cable is connected.

Common causes, most likely first

  1. A short to voltage in the control pilot circuit wiring, often due to chafed insulation or a pinched harness near the charge port.
  2. A faulty control pilot charging switch A that is stuck closed or has internal contamination.
  3. Corrosion or water intrusion at the charge port connector, causing abnormal voltage signals.
  4. A damaged or defective charge port assembly where the switch is integrated.
  5. A software glitch in the charging control module that misinterprets the switch signal.
  6. A poor ground connection for the charging system, causing reference voltage shifts.

How to diagnose and fix it

  1. Verify the code with a scan tool and check for any related charging system codes before clearing.
  2. Inspect the charge port and control pilot switch for physical damage, corrosion, or debris, and clean if necessary.
  3. Disconnect the battery and use a multimeter to check for continuity and voltage on the control pilot circuit at the switch and module connectors.
  4. Check the wiring harness from the charge port to the charging control module for shorts to voltage or chafed wires.
  5. Test the control pilot charging switch A for proper open and closed resistance values according to the service manual.
  6. If the switch or charge port assembly is faulty, replace it with a known-good unit and clear the code.
  7. After repairs, perform a charging system test and verify the code does not return.

Common misdiagnosis of control pilot faults

  • A high voltage on the control pilot circuit is often caused by a short to voltage in the harness rather than a failed switch, so always check wiring before replacing parts.
  • Water intrusion at the charge port can create intermittent high-voltage signals that mimic a faulty switch, especially after rain or car washes.
  • Some vehicles set this code when the 12-volt battery is weak or charging system voltage is unstable, so check battery health first.
  • The control pilot circuit is part of the charging communication protocol, and a fault here can prevent the vehicle from accepting a charge even if the switch tests good.
  • After any repair, a charging system reset or software update may be required to clear the code permanently on some models.

Can I keep driving with P0CFB?

You can usually drive the vehicle normally because this fault affects the charging system, not the drivetrain, but avoid relying on charging until the fault is repaired. If the vehicle is a plug-in hybrid or electric, plan to charge at a known-good station and monitor for any charging interruptions.

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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