Circuit Low means the pilot level sits under the lowest value any regular charging state can produce, as happens when the pilot wire is shorted to ground or to the protective earth contact. GM checks it in the Chevrolet Volt VICM/HPC2 tables from 2012 to 2019: with the cord unplugged, the controller feeds its own test signal through the internal diagnostic switch, and the ratio of pilot voltage to 12 V battery voltage must not fall below 0.03. 30 failures within 50 samples at 100 ms set the code as Type A, so the MIL lights after a single trip. A missing signal is P0CF3, an excessive level P0CF6, an implausible one P0CF4. While the line is pulled down, the vehicle cannot show the station that it is connected and ready, so charging does not begin.
Medium severity. Can I keep driving?If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
Symptoms
- Malfunction indicator lamp on (GM Type A)
- Station does not detect the vehicle, charging never starts
- Charge status indicator shows a fault after plugging in
Most likely causes
- Pilot wire chafed through and touching ground or the protective earth conductor
- Water or corrosion bridging pilot and earth pins in the charge inlet
- Failed pilot input or test circuit in the charging control module
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
What each character of P0CF5 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- C: Subsystem depends on the code range
- F5: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0CF5?
If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
What causes code P0CF5?
The most common causes are: pilot wire chafed through and touching ground or the protective earth conductor; water or corrosion bridging pilot and earth pins in the charge inlet; failed pilot input or test circuit in the charging control module.
Related codes
- P0CF3Control Pilot Circuit/Open
- P0CF4Control Pilot Circuit Range/Performance
- P0CF6Control Pilot Circuit High
- P0CF7Control Pilot Circuit Intermittent/Erratic
Sources
- gsi.ext.gm.com: 12OBDG01A HYBRID Diagnostics
- gsi.ext.gm.com: 16OBDG01 Hybrid Diagnostics
- gsi.ext.gm.com: 19OBDG01 Hybrid Diagnostics
- en.wikipedia.org: SAE J1772
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.