What it means
The control module detects a 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 measures air temperature near the hybrid or EV battery and sends its signal to the control module for battery management. This code sets when the module detects an electrical fault in sensor B’s circuit, without specifying that the signal is low, high, or intermittent.
Common causes
Most likely first.
- Failed air temperature sensor
- Open or shorted wiring
- Loose or corroded connector
Symptoms
- Hybrid system warning light
How to diagnose it
- Record freeze-frame data and compare sensor B’s reported temperature with sensor A, ambient conditions, and other battery temperature readings available on the scan tool.
- With the vehicle powered down as specified by its manufacturer, inspect sensor B’s connector and accessible wiring for looseness, corrosion, damage, or pinching.
- Check whether sensor B’s live reading changes plausibly and compare it with sensor A as battery conditions change.
- Use the wiring diagram to test sensor B’s circuit for opens, shorts, and poor connections.
- Measure sensor B and its circuit against manufacturer’s specifications to identify whether the sensor, wiring, or connector is at fault.
Common fixes
- Reseat and secure sensor B’s connector; clean or repair corroded terminals as appropriate.
- Repair damaged, loose, open, or shorted wiring in sensor B’s circuit.
- Replace a failed battery-pack air temperature sensor B.
- Repair a confirmed poor circuit connection or ground.
Can I keep driving?
The hybrid system may limit power or battery cooling if it cannot use sensor B’s reading. Drive gently and avoid long trips until diagnosed; stop if the warning comes with overheating, unusual battery behavior, or a major loss of power.
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.