What it means
The HV battery temperature sensor O 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
Sensor O measures the temperature of a section of the high-voltage battery so the battery control module can manage charging and power safely. This code sets when the Sensor O signal is above its permitted range, commonly because the signal wire is shorted to battery positive or the sensor circuit is open.
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
- Capture freeze-frame data and compare Sensor O’s live temperature with the other battery sensors; a very high or implausible value helps confirm the high-signal condition.
- Power the vehicle down using the manufacturer’s high-voltage safety procedure, then inspect Sensor O’s connector and harness for loose pins, corrosion, or damage.
- Check the Sensor O signal wire for a short to B+ and inspect for an open circuit using the vehicle wiring information.
- Test connector continuity and terminal contact, paying particular attention to corrosion or a pin that does not grip securely.
- If the circuit is intact, test Sensor O to the manufacturer’s specification and replace it if it is open or out of range.
Common fixes
- Reseat Sensor O’s connector and clean or repair corroded terminals.
- Repair the signal wire shorted to B+ or the open section of wiring.
- Replace Sensor O if it fails the manufacturer’s test.
Can I keep driving?
Avoid relying on normal charging or full electric power while Sensor O’s battery section temperature cannot be trusted. If power is limited or a battery warning appears, keep the trip short and stop safely if the vehicle’s response worsens.
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.