What it means
The control module detects a range or performance fault in the hybrid battery pack air temperature sensor B circuit.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Battery-pack air temperature sensor B reports the air temperature around the hybrid or EV battery, and the control module uses this input to manage battery operation and cooling. This code sets when sensor B’s reading is out of its expected range or responds poorly to changing conditions, even though it is not simply flagged as a low or high signal.
Common causes
Most likely first.
- Air temperature sensor fault
- Wiring or connector fault
- Sensor installation or contact problem
Symptoms
- Hybrid system warning light
How to diagnose it
- Review freeze-frame data and compare sensor B’s reading with sensor A, ambient temperature, and battery conditions.
- Check sensor B’s position and seating against the vehicle’s service information because poor placement can make its reading unrepresentative.
- Inspect sensor B’s connector and wiring for corrosion, loose terminals, damage, or chafing.
- Graph sensor B’s live data as battery conditions change and look for a response that is implausible or inconsistent with sensor A.
- Test sensor B and its circuit against manufacturer’s specifications to separate a sensor response problem from an installation or wiring fault.
Common fixes
- Correct sensor B’s position or seating if it is not installed as specified.
- Reseat the connector and clean or repair poor contacts in sensor B’s circuit.
- Repair damaged wiring or a poor connection affecting sensor B’s reading.
- Replace sensor B if its response fails the manufacturer’s tests.
Can I keep driving?
A range/performance fault may cause the hybrid system to restrict output or cooling because it cannot rely on sensor B’s reading. Keep driving gentle and brief, and stop if a hybrid warning appears with overheating or substantial power loss.
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.