What it means
The hybrid/EV battery pack coolant temperature sensor D circuit signal is below the expected range. The reading may be unreliable.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Sensor D measures coolant temperature in the hybrid or EV battery pack cooling system. The control module watches its signal to judge pack cooling needs; this code sets when the signal falls below the expected range, which can make the reported temperature unreliable.
Common causes
Most likely first.
- Signal wire shorted to ground
- Internal sensor short
- Connector pins corroded - high contact resistance
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
- Use a scan tool to record freeze-frame data and compare Sensor D's reported temperature with other available pack temperature readings and the ambient temperature.
- With the vehicle safely powered down according to its service instructions, inspect Sensor D's connector and accessible wiring for damage, moisture, corrosion, or a signal wire contacting ground.
- Check whether the Sensor D reading changes plausibly from a cold start as the battery pack warms, and note whether it stays implausibly low.
- Using the manufacturer's wiring diagram, test Sensor D's signal circuit for a short to ground and inspect connector pin contact.
- If the wiring and connections pass, test Sensor D and its circuit against the manufacturer's specification to distinguish a shorted sensor from a harness fault.
Common fixes
- Clean and secure corroded or loose Sensor D connector pins where serviceable.
- Repair a signal wire shorted to ground or damaged harness section.
- Replace Sensor D if it fails the manufacturer's electrical or temperature-response checks.
Can I keep driving?
Because an unreliable battery temperature reading can lead to reduced power or charging limits, avoid heavy acceleration and long trips if the vehicle enters limp mode or shows a battery-system warning. Stop if a battery-temperature or overheating warning appears, and arrange diagnosis promptly.
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.