Faulty HVAC air temperature internal sensor.; Damaged or corroded wiring or connector at the sensor.; Open or short circuit in the sensor signal or ground circuit.; Failed HVAC control module (less common).; Poor electrical connection at the control module harness.; Moisture or debris contamination in the sensor housing.

DTC codes / B02xx · Airbags, seats, doors, lights and comfort systems / B0250

B0250HVAC Air Temperature Internal Sensor Circuit

Q: What does code B0250 mean?

HVAC Air Temperature Internal Sensor Circuit. B0250 indicates that the HVAC (heating, ventilation, and air conditioning) control module has detected a fault in the internal air temperature sensor circuit, which measures the temperature of the air entering the cabin or inside the HVAC unit. The computer typically sets this code when the sensor signal voltage is out of range, intermittent, or absent, preventing accurate automatic temperature regulation.

B0250 indicates that the HVAC (heating, ventilation, and air conditioning) control module has detected a fault in the internal air temperature sensor circuit, which measures the temperature of the air entering the cabin or inside the HVAC unit. The computer typically sets this code when the sensor signal voltage is out of range, intermittent, or absent, preventing accurate automatic temperature regulation.

SystemBody

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

Often no symptoms besides the warning light, especially if the system defaults to a manual mode.
HVAC system may blow air at a fixed temperature regardless of settings.
Automatic climate control fails to maintain the set cabin temperature.
Temperature display may show incorrect readings or dashes.
Blower motor may run continuously or not at all in auto mode.
In some vehicles, the air conditioning compressor may be disabled.

Common causes, most likely first

Faulty HVAC air temperature internal sensor.
Damaged or corroded wiring or connector at the sensor.
Open or short circuit in the sensor signal or ground circuit.
Failed HVAC control module (less common).
Poor electrical connection at the control module harness.
Moisture or debris contamination in the sensor housing.

How to diagnose and fix it

Verify the code with a scan tool and check for any related HVAC codes.
Inspect the sensor connector and wiring for damage, corrosion, or loose pins.
Measure the sensor resistance and compare to the manufacturer's specification.
Check the signal voltage at the sensor connector with the key on, engine off.
Test the continuity of the signal and ground circuits between the sensor and HVAC control module.
Replace the sensor if it fails electrical tests.
If the sensor and wiring are good, diagnose or replace the HVAC control module as needed.

When the sensor isn't the real culprit

A common misdiagnosis is replacing the HVAC control module when the actual problem is a chafed wire behind the dashboard that intermittently shorts to ground.
The internal air temperature sensor is often mistaken for the ambient air temperature sensor, but they serve different purposes and have different locations.
On many vehicles, a failing blower motor resistor or final stage unit can cause voltage fluctuations that mimic a sensor circuit fault.
The code may set only when the HVAC system is in automatic mode, so testing in manual mode can help isolate the issue.
Corrosion at the sensor connector due to cabin leaks or windshield leaks is a frequently overlooked cause.

Can I keep driving with B0250?

The vehicle remains safe to drive because this fault only affects cabin comfort and does not impair engine, steering, or braking systems. You can continue driving, but avoid relying on automatic climate control until the issue is repaired.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.