What it means
The ECM detects a low fault on the generator inverter temperature sensor b 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
Generator inverter temperature sensor B reports temperature to the control module through an electrical signal circuit. This code sets when that signal is detected below its expected electrical range, which can happen with a signal short to ground or a shorted sensor and prevents reliable temperature monitoring.
Common causes
Most likely first.
- Signal wire shorted to ground
- Internal sensor short
- Connector pins corroded - high contact resistance
Symptoms
- Hybrid/EV system warning light on
- Power may be reduced if the inverter temperature cannot be monitored reliably
How to diagnose it
- Save freeze-frame data and check sensor B’s live reading for an unusually low or fixed value, comparing it with the other inverter temperature sensors.
- With the hybrid system powered down as specified by the manufacturer, inspect sensor B’s connector for corrosion, damaged terminals, or moisture.
- Trace the sensor B signal wire for a short to ground, chafing, or pinched insulation.
- Check connector terminal fit and continuity through the sensor B circuit using the manufacturer’s test procedure.
- Test sensor B separately against the manufacturer’s specification to determine whether the sensor itself is shorted.
Common fixes
- Clean or repair corroded sensor B connector terminals and ensure they seat securely.
- Repair a signal wire shorted to ground or other damaged wiring.
- Replace sensor B if it fails the manufacturer’s electrical test.
- Repair a confirmed fault at the control-module connector or its circuit.
Can I keep driving?
Avoid long trips, hard acceleration, and heavy loads because the control module may reduce hybrid power when it cannot monitor inverter temperature reliably. If the warning is accompanied by overheating signs or reduced power, stop in a safe place.
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.