What it means
The ECM detects a circuit fault on the dc/dc converter temperature sensor f 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
Temperature sensor F monitors a point in the DC/DC converter, which changes high-voltage hybrid-system power to lower-voltage power. This circuit code sets when the ECM detects a fault that makes sensor F's reading unreliable, but the code does not by itself specify whether the signal is too low or too high.
Common causes
Most likely first.
- Sensor failed
- Wiring or connector fault
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 sensor F live data for a missing, fixed, or implausible reading alongside other converter temperatures.
- With the hybrid system powered down as directed by service information, inspect sensor F's connector and wiring for damage, loose terminals, corrosion, or moisture.
- Check that sensor F is connected and seated correctly, then look for harness chafing or an open wire between the sensor and ECM.
- Test sensor F and its signal, reference, and ground circuits against the manufacturer's specification to distinguish a failed sensor from a wiring fault.
- If those checks pass, inspect the relevant ECM connector and verify the circuit at the module using the vehicle wiring information.
Common fixes
- Reconnect or secure sensor F's connector.
- Repair damaged or open sensor F wiring and poor terminal contact.
- Replace sensor F if its output fails the manufacturer's specification.
- Repair a confirmed ECM connector or circuit fault.
Can I keep driving?
Keep trips short and avoid heavy loads because the hybrid system may reduce power or lose dependable converter temperature monitoring. Stop if a hybrid temperature warning appears or the vehicle enters reduced-power operation.
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.