What it means
The control module detects an intermittent or erratic signal in the circuit for hybrid/EV battery temperature sensor A.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Battery temperature sensor A sends the control module a temperature signal from one monitored area of the hybrid or EV battery pack. This code sets when that signal becomes intermittent or erratic, such as when a connection briefly opens or the reading jumps unexpectedly.
Common causes
Most likely first.
- Intermittent wiring or connector fault
- Failed sensor
- Poor ground or connection
Symptoms
- Hybrid system warning light
How to diagnose it
- Save freeze-frame data and review sensor A's recorded temperature and related battery readings for sudden jumps or dropouts.
- Inspect the accessible sensor A connector and wiring for loose terminals, corrosion, chafing, or movement that could interrupt the signal.
- Watch sensor A live data while gently checking accessible harness sections for a change, following the manufacturer's safe procedure.
- Test the sensor A circuit connections and sensor response for intermittent faults using the manufacturer's procedure.
- If the wiring and sensor are stable, check the control-module input and grounds as specified by the manufacturer.
Common fixes
- Secure or repair a loose sensor A connector.
- Repair chafed or damaged sensor A wiring.
- Replace sensor A if its signal remains erratic during testing.
- Repair a confirmed poor ground or control-module circuit fault.
Can I keep driving?
Have the intermittent reading diagnosed soon because sudden loss of temperature data can lead to warnings or restricted hybrid operation. Avoid disturbing battery wiring and do not access high-voltage components.
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.