What it means
The HV battery temperature sensor J 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
The HV battery temperature sensor J supplies a signal used by the control module to monitor pack temperature and manage charging. This code sets when the sensor J circuit signal is lower than the module's expected range, commonly because the signal is pulled toward ground or the sensor is internally shorted.
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
- Record freeze-frame data and check live sensor J data for an abnormally low reading compared with nearby battery temperature channels.
- With the vehicle powered down as specified by the manufacturer, inspect the sensor J connector for corrosion, bent pins, contamination, or a poor fit.
- Inspect the accessible sensor J signal wiring for a short to ground, crushed insulation, or contact with grounded metal.
- Test the sensor J signal circuit for a ground short and check connector contact quality using the manufacturer's procedure.
- If wiring and terminals pass, test sensor J itself against the manufacturer's specification for a shorted element.
Common fixes
- Clean and secure the sensor J connector if contact is poor.
- Repair signal wiring shorted to ground.
- Replace corroded or damaged connector terminals.
- Replace sensor J if it fails the specified electrical test.
Can I keep driving?
A falsely low sensor J signal can make the hybrid system restrict power or charging. Drive only as needed and gently; stop if the vehicle loses substantial power or shows a battery temperature 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.