What it means
The HV battery temperature sensor I reports a circuit intermittent/erratic 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 I monitors a specific battery temperature channel, and the control module uses its signal to manage battery operation and charging. This code sets when the sensor I circuit signal changes erratically or intermittently instead of remaining plausible and stable.
Common causes
Most likely first.
- Connector not seated
- Noisy ground reference
- Connector with intermittent contact under vibration
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 I temperature with other battery temperature readings for sudden jumps or dropouts.
- With the vehicle powered down as specified by the manufacturer, inspect the sensor I connector for incomplete seating, damage, moisture, or contamination.
- Inspect the accessible sensor I wiring and connector strain points for looseness or damage that could open under vibration.
- Use a scan tool to watch sensor I data while checking the low-voltage harness and connector for a signal interruption, following the manufacturer's safety procedure.
- Test the sensor I circuit connections and ground reference against the manufacturer's specifications, then assess the sensor if wiring and connections are sound.
Common fixes
- Fully seat and secure the sensor I connector.
- Clean or repair poor connector contacts and restore a sound ground reference.
- Repair damaged or loose sensor I wiring.
- Replace the sensor I if it fails the manufacturer's circuit or plausibility checks.
Can I keep driving?
Because an unstable battery temperature reading can cause the hybrid system to limit power or charging, avoid long trips and heavy acceleration. Stop safely if power drops sharply or a battery warning appears, and arrange prompt diagnosis.
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.