Code Definition

B1003 — Mode changeover switch malfunction

System: Body  |  Type: Manufacturer-Specific  |  Make: Mitsubishi

About B1003

B1003 is a manufacturer-specific body diagnostic trouble code recorded for Mitsubishi vehicles. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

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.

B1003 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

This Mitsubishi-specific code is set when the climate control module detects a malfunction in the mode changeover switch circuit. The mode changeover switch (also referred to as the mode selection switch or airflow direction switch) is the control on the climate control panel that allows the driver to select the airflow distribution pattern — such as face vents, floor vents, defrost, or a combination of outlets. The switch typically uses a variable resistor or discrete contact positions to send a voltage signal to the climate control module indicating the selected mode. When this code is sto...

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