What it means
The ECM detects a circuit intermittent/erratic fault on the hybrid/ev battery pack air temperature sensor b circuit. Reading cannot be used reliably for control.
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 air temperature near the hybrid or EV battery, and the control module uses that reading when managing battery operation and cooling. This code sets when sensor B’s signal is intermittent or erratic, such as from a connector that loses contact with vibration or an unstable ground reference.
Common causes
Most likely first.
- Sensor 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
- Review freeze-frame data and graph sensor B’s live reading for dropouts or abrupt jumps, comparing it with sensor A and ambient conditions where available.
- Inspect sensor B’s connector for incomplete seating, loose pins, corrosion, or signs of movement; check accessible wiring for chafing or strain.
- With the vehicle handled according to manufacturer safety instructions, gently move the accessible sensor B harness while watching live data for a reproducible interruption.
- Check sensor B’s ground and circuit connections for unstable contact using the wiring diagram and manufacturer’s procedures.
- Test sensor B and its circuit for stable operation against manufacturer’s specifications before replacing components.
Common fixes
- Reseat and secure sensor B’s connector.
- Repair loose, corroded, or damaged terminals and wiring in sensor B’s circuit.
- Repair a noisy or poor ground reference confirmed by testing.
- Replace sensor B if its signal remains erratic with sound wiring and connections.
Can I keep driving?
An intermittent sensor B signal can trigger reduced output or limp mode and may interrupt or slow charging, reducing electric range. Keep trips short and gentle until repaired, and stop if the vehicle shows overheating or a sudden unsafe 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.