P0CFB

Code

Generic P — Powertrain

Control Pilot Charging Switch A Circuit High

Brand: Generic

Type: P — Powertrain

Views: UK: 18 EN: 39 RU: 28

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Page language: EN

Causes

Open or high-resistance wiring between control module and charging inlet/relay
Short or unintended connection to battery positive (voltage backfeed)
Faulty charging relay, contactor or switch associated with Control Pilot A
Corroded/loose connector or damaged pins at the charging inlet, control module, or relay
Faulty control module or charging controller output transistor
Aftermarket accessories or repairs that altered wiring/harness

Symptoms

Charging disabled or stops unexpectedly
Charge port/EV charge fault light or warning message on dash
DTC P0CFB stored and possibly other related charging codes
Intermittent charging behavior or inability to start a charge session
No proper control pilot signal present at charge inlet

What to check

Read and record freeze frame and all stored charging-related codes; clear codes and attempt to reproduce
Perform a visual inspection of charging inlet, wiring harness, connectors, and protective boots for damage, corrosion, or water
Check fuses and relays related to charging/control pilot circuits
Backprobe the control pilot wiring at the control module and at the charge inlet to compare voltages
Measure continuity and resistance between control module pin and charge inlet/relay (with power off)
Inspect for aftermarket devices or recent repairs that could have altered wiring

Signal parameters

Expected: control pilot is typically a low-voltage signal that is actively driven/pulled low by the vehicle controller and should switch between near 0V and a reference voltage (commonly in the single-digit to low 12V range depending on architecture)
Typical pilot signals are pulsed or switched; absence of expected pulsing or a steady high voltage indicates a fault
A circuit reported as 'high' means the measured voltage is above the expected upper threshold or the line is being pulled toward battery voltage when it should be driven/pulled low
Exact voltage and frequency depend on manufacturer; consult vehicle service information for nominal thresholds and waveform shapes

Diagnostic algorithm

Retrieve freeze-frame, note vehicle state when DTC set (charging, accessory, ignition). Clear code and try to reproduce under same conditions.
Visually inspect charge inlet, control pilot connector, related relays/fuses, and wiring harness for damage, corrosion, or water ingress.
With vehicle ignition per manufacturer instructions, backprobe the control module pin for Control Pilot A and the charge inlet pilot pin. Compare measured voltages to expected values in service data.
Check continuity and resistance between the control module and the charging inlet/relay with power off. Look for opens or high resistance.
Isolate and test the charging relay/contactor: verify coil drive and contact operation. Replace or bench-test relay if suspect.
Inspect for and remove any unintended voltage sources on the pilot wire (short to B+). Disconnect downstream connectors (charge inlet) and re-check circuit voltage to see if fault follows connector or stays at module.

Likely causes

Open or disconnected pilot/relay wiring (most likely)
Connector corrosion or damaged pins at the charge inlet/relay
Failed charging relay/switch or stuck open device causing abnormal voltage
Control module/charger driver transistor failure (less common)
Short to battery voltage through harness or accessory (possible)

Fault status

⚠️ Status

Control Pilot Charging Switch A Circuit High — charging pilot line voltage above expected threshold. Charging may be disabled until fault is cleared or repaired.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours