What it means
The ECM detects a circuit high fault on the dc/dc converter 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
DC/DC converter temperature sensor D sends a temperature signal to the control module from its designated converter location. This circuit-high code sets when the signal voltage is higher than expected, commonly because the signal wire is shorted to battery voltage, the sensor circuit is open, or a corroded connector interrupts the path.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open sensor
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine light or hybrid-system warning
- Reduced hybrid power or performance
- Hybrid-system temperature warning
How to diagnose it
- Save freeze-frame data and check for related converter temperature codes to determine whether the high reading is isolated to sensor D.
- Read sensor D’s live temperature and compare it with other converter readings; a fixed or implausibly low temperature can indicate a high signal fault.
- With the vehicle safely powered down under its service procedure, inspect sensor D’s connector and wiring for an unplugged connector, pushed-back pin, corrosion, or contact with a power wire.
- Test the sensor D circuit for an open and for a short to battery voltage, then verify terminals and circuit continuity against the manufacturer’s specification.
- If the wiring and connector pass, test sensor D according to the manufacturer’s procedure to check for an internal open.
Common fixes
- Reconnect sensor D’s connector and secure it if it has come loose.
- Repair an open or damaged wire in the sensor D circuit.
- Repair any signal wire short to battery voltage and restore corroded connector contacts.
- Replace sensor D if it has an internal open or fails its specified test.
Can I keep driving?
The vehicle may reduce hybrid power because it cannot trust the converter’s temperature D reading. Avoid heavy loads and stop safely if a temperature warning or power restriction appears, since the fault can prevent proper thermal protection.
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.