What it means
The control module detects a fault in the hybrid battery pack air temperature sensor A 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 A reports the temperature of air around the hybrid or EV battery to the control module, which uses the reading to manage battery cooling and operation. This code sets when the module detects an electrical fault in sensor A’s circuit, without identifying a specific low, high, or erratic signal condition.
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
- Use a scan tool to record freeze-frame data and compare sensor A’s reported temperature with other battery temperature readings and ambient conditions.
- With the vehicle powered down as specified by its manufacturer, visually inspect sensor A’s connector and accessible wiring for looseness, corrosion, damage, or pinched sections.
- Check whether sensor A’s live reading changes plausibly as battery conditions change and compare it with sensor B if the vehicle provides that data.
- Test sensor A’s wiring for opens, shorts, and poor connections, following the vehicle’s wiring diagram and manufacturer’s procedures.
- Measure sensor A and its circuit against the manufacturer’s specifications to distinguish a sensor fault from a wiring or connector fault.
Common fixes
- Reseat and secure sensor A’s connector; clean or repair corroded terminals as appropriate.
- Repair damaged, loose, open, or shorted wiring in sensor A’s circuit.
- Replace a failed battery-pack air temperature sensor A.
- Repair a confirmed circuit ground or connection fault.
Can I keep driving?
Because the hybrid system may limit power or battery cooling when sensor A’s reading is unavailable, avoid hard acceleration and long trips until the fault is diagnosed. Stop safely if a hybrid system warning is accompanied by 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.