What it means
The HV battery temperature sensor L reports a circuit low 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 lower than the module's expected electrical range, which can result from a short to ground, a sensor fault, or poor terminal contact.
Common causes
Most likely first.
- Signal wire shorted to ground
- Internal sensor short
- 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 capture freeze-frame data and check whether Sensor L shows an implausibly low, fixed, or missing temperature.
- Compare the L reading with other battery temperature channels to confirm the abnormal signal is specific to Sensor L.
- With the vehicle powered down according to its service information, inspect the L connector and harness for corrosion, damaged insulation, or a wire contacting ground.
- Have a qualified hybrid technician test the L signal circuit for a short to ground and check connector contact condition using the wiring diagram and manufacturer's procedure.
- If the circuit is not shorted and its connections are sound, test Sensor L and replace it only if it fails the specified checks.
Common fixes
- Repair damaged L-channel wiring that is shorted to ground.
- Clean or repair corroded or high-resistance Sensor L connector terminals.
- Replace Sensor L if testing confirms an internal short or failed sensor.
- Clear the fault and verify that the L-channel reading returns to a plausible value.
Can I keep driving?
The module may limit battery power or charging because the Sensor L signal is abnormally low. Keep driving limited and gentle, and stop safely if power becomes restricted or a high-voltage battery warning appears; do not work on high-voltage components yourself.
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.