What it means
The HV battery temperature sensor I 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
HV battery temperature sensor I monitors the temperature of its assigned cell group for the battery management system. P0C8B sets when the sensor I circuit signal is abnormally high, which can indicate a signal short to battery voltage, an open sensor, or a poor connector contact.
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
- Use a hybrid-capable scan tool to save freeze-frame data and compare sensor I's reported temperature with nearby battery sensors for a fixed or implausibly high reading.
- Inspect the sensor I connector and wiring for loose or corroded pins, damaged insulation, and contact between the signal wire and a power feed.
- With the high-voltage system made safe using the manufacturer's procedure, check sensor I circuit continuity and connector condition.
- Test the sensor I signal circuit for a short to battery voltage using the manufacturer's wiring diagram and procedure.
- If no wiring short is found, test sensor I for an open element or circuit against the manufacturer's specifications.
Common fixes
- Clean or secure a corroded sensor I connector connection.
- Repair the sensor I signal wire if it is shorted to a power feed or otherwise damaged.
- Replace sensor I if it fails the specified open-circuit or sensor test.
- Clear the fault and verify that sensor I reports a plausible temperature.
Can I keep driving?
Avoid charging and hard driving while the hybrid warning or reduced-power mode is active, since the battery controller may limit operation when sensor I cannot provide a reliable temperature reading. Stop if a battery-temperature warning appears or power drops substantially.
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.