Diagnostic article Generic OBD-II
P0CF5: Control pilot low during GM’s disconnected-cord test
P0CF5 identifies a low normalized control-pilot signal during the documented GM diagnostic-switch test.
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Documented application
15OBDG01 Hybrid Diagnostics, cited controller and monitor only. Historical calibration limits are not universal specifications; per-code vehicle, engine and hardware applicability must be verified.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
Why the unplugged state matters
P0CF5 in GM’s 2015 hybrid diagnostic table is a control-pilot circuit-low result obtained under a particular self-test state. The charge cord must be reported not connected, the control-pilot diagnostic switch must be on, and system voltage must exceed 9 volts. It is therefore misleading to describe this monitor simply as insufficient current coming from a charging station.
The controller evaluates the pilot signal as a percentage of system voltage. A value below 3% meets the electrical failure criterion. This normalization matters: the percentage is a relationship between two voltages, not the charging station’s advertised amperage or the traction battery’s state of charge.
Evidence that separates the fault paths
The table requires 30 failed observations within 50 samples taken at 100-millisecond intervals. An isolated low reading cannot be equated with the complete detection sequence. It also specifies a five-second passing period, so one satisfactory snapshot does not establish that the diagnostic has passed.
For a technician, the useful record contains pilot percentage, system voltage, cord-detection state and diagnostic-switch state together. A low reading while the switch is not commanded into the documented test state does not reproduce this particular monitor. Conversely, a scan report showing an unplugged-cord state deserves comparison with the actual connection history before blaming external charging equipment.
This source describes detection logic, not an approved pin-probing or component-replacement procedure. Matching vehicle service information is needed before diagnosing the charging interface; the percentage threshold is not a specification for every vehicle using P0CF5.
Source and applicability
15OBDG01 Hybrid Diagnostics, cited controller and monitor only. Historical calibration limits are not universal specifications; per-code vehicle, engine and hardware applicability must be verified.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Control Pilot Circuit Low
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT