What it means
The hybrid/EV battery pack coolant temperature sensor D circuit signal is above 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 uses its signal to assess pack cooling; this code sets when the circuit signal rises above the expected range, so the reported temperature may not be trustworthy.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open sensor
- 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 save freeze-frame data and compare Sensor D's reported temperature with other pack temperature readings and ambient temperature.
- With the vehicle safely powered down according to its service instructions, inspect Sensor D's connector and wiring for an open, corrosion, damage, or contact with a B+ supply.
- Check live data from a cold start for a Sensor D value that is implausibly high or fixed while other temperature readings behave normally.
- Use the manufacturer's wiring diagram to test the signal circuit for a short to B+ and check connector pin contact and continuity.
- If the harness checks pass, test Sensor D and its circuit against the manufacturer's specification for an open sensor or other internal fault.
Common fixes
- Clean and secure corroded or loose Sensor D connector pins where serviceable.
- Repair an open circuit or signal wire shorted to B+.
- Replace Sensor D if it fails the manufacturer's tests.
Can I keep driving?
The vehicle may limit power or charging because it cannot rely on the battery coolant temperature reading. Avoid strenuous driving if power is restricted, and stop if a battery-temperature or overheating warning appears.
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.