What it means
The BMS detects a circuit fault on voltage sense channel Z 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 battery management system monitors voltage sense channel Z to estimate the voltage of its associated cell group in the high-voltage battery. This code indicates a fault in that channel's measurement path, so the reported Z-group voltage is unreliable.
Common causes
Most likely first.
- Sense circuit failed
- Wiring fault
- Pack cell imbalance approaching service threshold
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 compare channel Z with the other battery voltage readings to determine when the fault was recorded.
- Check whether the warning, reduced power, or charging restriction occurred at the same time as the channel Z fault.
- Have a qualified hybrid technician inspect channel Z's sense wiring and connector for damage, corrosion, loose terminals, or an open circuit.
- With the high-voltage system made safe using the manufacturer's procedure, test channel Z's circuit continuity and compare its reading with the manufacturer's specifications.
- If the channel circuit passes, assess the associated cell group for imbalance and check the battery management system's channel Z input.
Common fixes
- Reseat a loose channel Z connector.
- Clean or repair corroded channel Z terminals.
- Repair or replace damaged or open channel Z wiring.
- Service the battery sensing component or cell group if testing confirms it is outside the manufacturer's specifications.
Can I keep driving?
Drive only as needed if the hybrid warning is on or power and charging are limited; the vehicle may enter limp mode and electric range can decrease. Arrange prompt diagnosis and stop safely if a red warning or major loss of power appears.
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.