What it means
The HV battery temperature sensor J 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
The HV battery temperature sensor J sends a temperature signal to the control module for battery protection and charging control. This code sets when the sensor J circuit voltage is higher than expected, which can happen with an open circuit or a signal shorted to battery positive.
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
- Record freeze-frame data and compare live sensor J temperature with nearby battery readings for an implausibly high or fixed value.
- With the vehicle powered down as specified by the manufacturer, inspect the sensor J connector for a loose fit, corrosion, or backed-out terminals.
- Inspect accessible sensor J wiring for an open conductor or insulation damage that could allow contact with a power feed.
- Test the sensor J circuit for continuity and for an unintended connection to battery positive, following the manufacturer's procedure.
- If the harness and connector pass, test sensor J for an open element against the manufacturer's specification.
Common fixes
- Reseat the sensor J connector and secure loose terminals.
- Repair an open or damaged sensor J wire.
- Repair wiring that is shorted to battery positive.
- Replace sensor J if its element is open or outside specification.
Can I keep driving?
The control module may limit power or charging because it cannot trust the sensor J temperature signal. Avoid long journeys and heavy loads, and stop if a battery warning or significant power reduction 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.