What it means
The HV battery pack cooling fan 1 sense circuit reports a sense circuit/open fault. Fan speed feedback is unreliable.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The hybrid battery cooling fan moves air through the high-voltage battery pack, and its sense circuit reports fan speed to the control module. P0BC7 sets when the fan 1 speed-feedback circuit is open or cannot provide reliable feedback, which may be caused by an open sense wire, failed fan tachometer, or a pin pushed back in its connector.
Common causes
Most likely first.
- Open in sense wire
- Fan tachometer failed
- Pin pushed back out of connector body
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 live fan command and speed feedback, if available, to see whether the module requests fan 1 operation but receives no reliable speed signal.
- With the vehicle powered down as specified by service information, inspect the fan 1 connector for a pushed-back pin, incomplete seating, corrosion, or harness damage.
- Check the accessible fan 1 sense wire and terminals for an open, using the manufacturer's wiring information to identify the correct circuit.
- If the sense wire and connections are intact, test fan 1's tachometer output and related circuit according to the manufacturer's procedure.
- After repairs, confirm fan 1 speed feedback responds when commanded and verify that the fault does not return.
Common fixes
- Reseat the fan 1 connector and correctly position any pushed-back terminal.
- Repair an open or damaged fan 1 sense wire.
- Replace the fan assembly if its tachometer fails the specified test.
- Clear the code and confirm fan 1 feedback follows commanded operation.
Can I keep driving?
Avoid heavy driving and charging, which increase battery heat, and stop if the vehicle limits power or shows an urgent hybrid warning. Without dependable fan speed feedback, the system may restrict operation and the battery may not receive the expected cooling.
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.