P0CF4 flags a pilot signal that is electrically present but does not fit what the vehicle expects. GM spells out the test for the Chevrolet Volt (2011-2019, VICM/HPC2): with no cord connected and the car moving at 8 km/h or more, pilot voltage divided by battery voltage must stay below 0.03 and both processor logic states must agree; in a self-test with the internal diagnostic switch closed and the charging and ventilation switches open, the ratio must sit between 0.30 and 0.55. 30 of 50 samples at 100 ms set it as Type A, MIL after one trip; older tables also require the charge door to be closed. FCA names P0CF4-00 together with P0CF3 on the Pacifica Plug-in Hybrid and the Renegade/Compass 4xe and fixes it by reflash. Opens and shorts have their own codes. Charging may fail or be refused.
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 after one trip (GM)
- Charging refused or interrupted
- Charge status indicator shows a fault
Most likely causes
- Faulty pilot measuring or self-test circuit inside the charging/hybrid control module
- Module software needing an update (FCA Pacifica and 4xe bulletins)
- Moisture or dirt in the charge inlet creating a leakage path on the pilot line
- Charge door position fault blocking or distorting the test (GM Volt enable condition)
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 P0CF4 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- C: Subsystem depends on the code range
- F4: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0CF4?
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 P0CF4?
The most common causes are: faulty pilot measuring or self-test circuit inside the charging/hybrid control module; module software needing an update (FCA Pacifica and 4xe bulletins); moisture or dirt in the charge inlet creating a leakage path on the pilot line.
Related codes
- P0CF3Control Pilot Circuit/Open
- P0CF5Control Pilot Circuit Low
- P0CF6Control Pilot Circuit High
- P0CF7Control Pilot Circuit Intermittent/Erratic
- P0CF9Control Pilot Charging Switch A Range/Performance
- P0D01Control Pilot Charging Ventilation Switch Range/Performance
- P0CCCCharge Port Door A Position Sensor Circuit
Sources
- gsi.ext.gm.com: 11OBDG01 HYBRID Diagnostics
- gsi.ext.gm.com: 16OBDG01 Hybrid Diagnostics
- gsi.ext.gm.com: 19OBDG01 Hybrid Diagnostics
- static.nhtsa.gov: MC 10215947 9999
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.