What it means
The ECM detects a range/performance 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 so the battery management system can track pack voltage. This code sets when the F reading is present but falls outside the expected range or fails to respond as expected, indicating a performance problem rather than a simple low or high circuit signal.
Common causes
Most likely first.
- Fault in the voltage-sensing circuit
- Damaged wiring or poor connector contact
- 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 review related battery codes to identify the operating conditions and whether the F reading changes with pack conditions.
- Compare live F-circuit data with the other pack-sensing readings and check whether F is implausible, unstable, or inconsistent with the pack.
- With the vehicle powered down by the manufacturer's procedure, inspect accessible F-circuit wiring and connectors for damage, corrosion, poor contact, or moisture.
- Have a qualified hybrid technician test the F circuit and connections for continuity and contact quality using the manufacturer's safety procedure.
- If wiring is sound, test the F voltage-sensing component and module input against the manufacturer's diagnostic procedure.
Common fixes
- Clean and reseat a poor-contact F-circuit connector.
- Repair damaged or corroded F-circuit wiring and terminals.
- Replace a confirmed faulty F voltage-sensing component.
- Repair or replace a module only if its input fails the manufacturer's tests.
Can I keep driving?
Limit driving, especially journeys that depend on full hybrid or electric power, because the vehicle may reduce output and charging may be restricted. If the vehicle enters limp mode or shows a high-voltage warning, 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.