P0CF6: High control-pilot percentage with no charge cord connected

What the controller is checking

The P0CF6 row in GM’s 2015 hybrid diagnostic tables concerns an unexpectedly high control-pilot percentage when the charge cord is not connected. Its printed threshold is greater than 58%, with system voltage above 9 volts. This is an electrical interface check under a disconnected-cord condition, not a measurement of battery charging speed.

The percentage describes the pilot signal relative to system voltage. A high percentage does not mean the battery is overcharged, nor does this row establish that a public charging station delivered excessive current. Those interpretations confuse the pilot measurement with the power delivered through the charging circuit.

What to preserve for diagnosis

The monitor counts 30 failures among 50 samples and lists a five-second passing period. However, the original row truncates its strategy and timing details: it does not provide a readable sampling interval. The 100-millisecond interval printed for adjacent P0CF5 must not be silently assigned to P0CF6.

A useful diagnostic comparison therefore includes the recorded pilot percentage, low-voltage supply and cord-connection status, with the failure identified as current or historical. Reproducing only the numerical threshold while a cord is connected would miss an explicit condition of this monitor. Similarly, an unplugged vehicle with no recorded passing run is not proof that a previous failure has been repaired.

This historical table establishes the supported high-signal condition but does not identify a failed component. The incomplete timing text requires confirmation in applicable service information before relying on a precise test duration or replacement decision.

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.

GM source, physical page 596.