What it means
The BMS detects a circuit intermittent/erratic fault on voltage sense channel R of the high-voltage battery. Cell-group voltage measurement is unreliable on this channel.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The BMS monitors voltage sense channel R to track one cell group in the high-voltage battery. P0B94 sets when the channel R signal fluctuates or behaves erratically, so the BMS cannot rely on that group’s voltage reading.
Common causes
Most likely first.
- Sense connector not seated
- Noisy ground reference
- Connector with intermittent contact under vibration
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 channel R live data for dropouts or sudden changes, noting whether the fault coincides with vibration or vehicle operation.
- With the vehicle powered down as the manufacturer specifies, inspect channel R’s accessible connector and wiring for a loose fit, damage, or corrosion.
- Have a qualified hybrid technician verify that the channel R connector is fully seated and that its terminals maintain contact.
- Use the manufacturer's procedure to check channel R’s ground reference and wiring continuity while looking for an unstable connection.
- If the harness and ground remain stable, follow the manufacturer's diagnostic procedure to assess the battery monitoring input for channel R.
Common fixes
- Reseat the channel R connector and secure it as specified.
- Clean or replace channel R terminals with intermittent or corroded contact.
- Repair a damaged channel R wire or unstable ground connection.
- Repair or replace the battery monitoring component if tests isolate the fault there.
Can I keep driving?
Driving may trigger reduced power or limp mode if channel R drops out, and charging may be restricted. Avoid long trips and arrange prompt diagnosis; stop safely if power becomes unpredictable.
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.