What it means
The ECM detects a circuit low fault on the drive motor inverter temperature sensor d circuit. Reading cannot be used reliably for control.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Inverter temperature sensor D reports the temperature at its monitored point in the drive motor inverter to the ECM. The ECM sets P0BD8 when the D signal circuit voltage falls below its acceptable range, so it cannot rely on that temperature reading to manage the hybrid or EV system.
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 motor power or torque
- Possible limp mode or vehicle shutdown
How to diagnose it
- Read the freeze-frame and hybrid control data for sensor D, and note whether the fault appears with the inverter cold, hot, or under load.
- With the vehicle powered down as specified by the manufacturer, inspect sensor D's connector and wiring for damage, moisture, corrosion, or a pinched signal wire.
- Check the D signal circuit for a short to ground and inspect its ground reference and connector contacts using the manufacturer's procedure.
- Compare sensor D's live reading with other available inverter temperature readings and ambient conditions to identify an implausibly low value.
- If wiring and connections pass, test sensor D and its circuit against the manufacturer's specification before considering a sensor or control-module fault.
Common fixes
- Clean and correctly seat a corroded or loose sensor D connector, repairing damaged terminals as needed.
- Repair a signal wire or connector shorted to ground.
- Replace a failed inverter temperature sensor D if it fails the manufacturer's test.
- Repair a verified circuit fault or, only after circuit checks, address a control-module fault.
Can I keep driving?
Avoid hard acceleration, steep climbs, and long trips because the vehicle may limit motor output or shut down if inverter temperature cannot be monitored reliably. If it enters limp mode or displays a stop warning, pull over safely and arrange service.
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.