What it means
The HV battery temperature sensor L reports a circuit high fault. Cell-group temperature monitoring impaired on this channel.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Sensor L measures temperature at its assigned area of the high-voltage battery, and the hybrid control module reads its signal to manage battery power and charging. This code sets when the L-channel signal is higher than the module's expected electrical range, which can be caused by an open sensor circuit, a short to battery positive, or poor terminal contact.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open sensor
- Connector pins corroded - high contact resistance
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
- Use a compatible scan tool to save freeze-frame data and check whether Sensor L is fixed, missing, or implausibly high.
- Compare the L reading with other battery temperature channels to confirm the fault is confined to the L channel.
- With the vehicle powered down according to its service information, inspect the L connector and wiring for an unplugged connection, corrosion, damaged insulation, or an open wire.
- Have a qualified hybrid technician test the L circuit for an open and for a short to battery positive, following the wiring diagram and manufacturer's procedure.
- If the wiring and connector pass, test Sensor L and replace it if the specified checks confirm an open or failed sensor.
Common fixes
- Reconnect and secure a loose Sensor L connector.
- Repair an open or damaged wire in the L-sensor circuit.
- Repair a signal wire shorted to battery positive.
- Replace Sensor L if testing confirms it is open or faulty.
Can I keep driving?
The module may restrict power or charging because it cannot rely on the Sensor L signal. Limit driving and avoid heavy acceleration; stop safely if a battery warning appears or the vehicle loses power, and leave high-voltage circuit repairs to a qualified hybrid technician.
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.