What it means
The HV battery temperature sensor O reports a range/performance 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 O measures temperature at its assigned area of the high-voltage battery, and the control module compares its reading with expected values and other battery sensors. This code sets when the O reading is outside the expected range or responds implausibly, which can happen if the sensor has drifted or shifted from its intended mounting.
Common causes
Most likely first.
- Sensor characteristic drifted
- Sensor mounting displaced
- Sensor element aged beyond calibration window
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
- Review freeze-frame data and compare Sensor O live temperature with other battery sensors under similar conditions for an implausible offset or response.
- With the vehicle powered down per the manufacturer's procedure, inspect Sensor O's mounting and contact at its monitored battery area for displacement.
- Inspect the O connector and harness for poor contact or damage that could skew the reading.
- Check Sensor O's response as battery temperature changes using the manufacturer's diagnostic procedure.
- Test Sensor O against the manufacturer's specification and check the module input if the installation and wiring are sound.
Common fixes
- Correct Sensor O's mounting or contact if it has shifted.
- Repair poor connections or damaged wiring in the O sensor circuit.
- Replace Sensor O if its reading is outside the manufacturer's specification.
- Repair the module connection or replace the control module only if testing confirms an input fault.
Can I keep driving?
The vehicle may limit power or charging if it cannot rely on Sensor O to assess battery temperature. Avoid heavy acceleration and long trips until the fault is diagnosed, and follow any stop warning.
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.