Code Definition

B0189 — Sun load sensor signal out of range - sensor 2

System: Body  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About B0189

B0189 is a generic (obd-ii standard) body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B0189 is stored, the module has detected a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: Body (B) codes are often stored in the body control module, airbag module, or climate module. A basic OBD-II tool usually will not read body codes — an enhanced or OEM-level scan tool is typically required.

Because B0189 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The HVAC control module monitors a 0-5V signal from sun load sensor 2, the secondary photodiode used on dual-zone climate systems to measure solar radiation on the passenger side of the dash. The module compares the sensor voltage against high and low thresholds and uses the value to bias passenger-side blower output and discharge temperature when sunlight enters the cabin. DTC B0189 sets when the sensor 2 voltage is detected above the maximum or below the minimum allowable range for a calibrated period — typically a hard short to voltage, short to ground, or open circuit condition rather th...

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