Code Definition

B0188 — Sun load sensor signal error - sensor 1

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

About B0188

B0188 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 B0188 is stored, the module has detected 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 B0188 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 the signal from sun load sensor 1, a photodiode located in the dash top that measures solar radiation entering the cabin. This input is used to bias blower speed and discharge air temperature when sunlight is heating the interior. DTC B0188 sets when the control module detects an invalid, erratic, out-of-range, or missing signal from sensor 1 — typically a stuck-high, stuck-low, or wildly fluctuating reading that does not correlate with cabin conditions. With this fault active, automatic climate control may overcool or undercool the cabin in direct sunlight a...

Join TaT to view the complete code information and diagnostic details.

Quick Facts