What it means
The ECM detects a intermittent/erratic fault on the hybrid/ev battery pack voltage sense f circuit. Reading cannot be used reliably for control.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Voltage-sense circuit F monitors a portion of the hybrid or EV battery pack. This code sets when the F reading becomes intermittent or erratic, suggesting a connection or sensing fault that makes the value unreliable even if it sometimes returns to normal.
Common causes
Most likely first.
- Intermittent wiring or connector fault
- Poor electrical connection in the voltage-sensing circuit
- Voltage-sensing component fault
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
How to diagnose it
- Save freeze-frame data and check code history to learn whether the F fault appears during particular operating conditions or alongside other battery-sensing codes.
- Watch live F-circuit data alongside other pack-sensing readings for dropouts or sudden changes while the vehicle is stationary and safely powered as directed by the manufacturer.
- With the vehicle powered down by the manufacturer's procedure, inspect accessible F-circuit wiring and connectors for looseness, corrosion, chafing, or moisture.
- Have a qualified hybrid technician check F-circuit connection quality and wiring continuity, including for a fault that appears intermittently, using the manufacturer's safety procedure.
- If the wiring and connections are sound, test the F voltage-sensing component and module input for intermittent failure.
Common fixes
- Secure and clean an intermittently contacting F-circuit connector.
- Repair chafed or damaged F-circuit wiring and terminals.
- Replace a confirmed intermittently faulty F voltage-sensing component.
- Repair or replace the module only if its F input fails testing.
Can I keep driving?
Avoid long journeys and hard acceleration because the fault may return without warning and trigger reduced power or charging. If the warning is accompanied by limp mode or a high-voltage system alert, stop safely and arrange qualified hybrid service.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.