P0C94
Hybrid/EV Battery Temperature Sensor K Circuit Low.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- C
- AreaHybrid propulsion
- 94
- FaultThe specific fault in that area
What it means
P0C94 is a generic powertrain code meaning the hybrid or EV control unit has detected a low signal from the traction battery temperature sensor designated 'K'. The voltage on the sensor circuit has dropped below the expected range, which typically points to a short to ground, a faulty sensor or a wiring problem. Which physical sensor 'K' refers to, and where it sits in the battery pack, depends on the model and battery design.
Symptoms
- Hybrid or EV system warning light on the dashboard
- Malfunction indicator lamp illuminated
- Reduced power or limited acceleration (limp mode)
- Reduced electric-only range or altered charging behaviour
- Battery cooling fan running constantly or erratically
- Car refusing to enter ready mode or to charge (in some cases)
Possible causes
- Faulty battery temperature sensor reading falsely low (internal short or drift)likely
- Sensor signal wire chafed or shorted to ground in the pack harnesslikely
- Damaged, corroded or contaminated connector at the sensor or battery monitoring modulepossible
- Moisture or coolant ingress affecting the sensor circuit or connectorpossible
- Fault in the battery monitoring module or hybrid control unit input circuitrare
- Outdated control unit software that is a known cause on some models (manufacturer bulletin dependent)rare
How to diagnose
- Read all stored and pending codes and record the freeze frame data to see battery state and temperatures when the fault set.
- Check for other battery temperature or battery monitoring codes that might point to a shared wiring or module fault.
- Using live data, compare the sensor K reading with the other pack temperature sensors and with ambient temperature when the car is cold; a reading that is implausibly low suggests a sensor or circuit fault.
- Follow the manufacturer's high-voltage safety procedure, and only proceed if trained and qualified to work on high-voltage systems.
- Inspect accessible wiring and connectors for damage, corrosion, moisture or pin tension problems.
- Disconnect the sensor and measure its resistance against the manufacturer's temperature specification.
- Test the signal circuit for a short to ground and check the reference supply and ground at the connector.
- Check for any applicable software updates or technical service bulletins for the specific model.
How to fix
- Replace the faulty battery temperature sensor, or the sensor assembly if supplied only as part of the pack component.
- Repair or replace the damaged wiring section, ensuring correct routing and insulation.
- Clean, dry or replace corroded or damaged connectors and terminals.
- Trace and rectify the source of moisture or coolant ingress, then dry and repair affected parts.
- Replace the battery monitoring module or control unit only if testing proves it faulty, then clear the code and road test.
- Apply an updated control unit calibration where the manufacturer lists it as the fix for this fault.
Can I keep driving?
The car may be driven carefully for a short time, but the system may restrict power and charging as it cannot monitor pack temperature properly. Book it in soon, and stop driving if a red warning appears or the car loses drive.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.