Heater Coolant Temp sensor circuit Short to GND
The heater coolant temperature sensor is shorted to ground, meaning the electrical signal is stuck at zero instead of varying with temperature. Think of it like a light switch that's permanently jammed in the 'on' position, sending a false signal to the engine computer.
The ECM monitors the heater coolant temperature sensor's voltage signal to regulate coolant flow to the heater core and maintain cabin temperature. The sensor normally produces a variable voltage (high when cold, low when hot) as coolant temperature changes. A short to ground forces the voltage to 0V constantly, signaling an impossible fault condition.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Sensor voltage | 0.5V to 4.5V (variable with temperature) | Below 0.1V (stuck at ground) |
| Coolant temperature reading | -40°C to 130°C range | Fixed at -40°C or invalid reading |
Code B2380 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.
Once the fault is repaired, B2380 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.