Code Definition

B1271 — Servo Motor Potentiometer Defrost Circuit Short To Ground

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

About B1271

B1271 is a manufacturer-specific body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1271 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit.

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.

B1271 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

The HVAC mode door servo motor uses an internal potentiometer to provide position feedback to the climate control module, allowing the module to know the actual position of the defrost mode door and drive the servo to the commanded position. The potentiometer is supplied with a 5V reference voltage, a ground return, and a wiper feedback signal that varies as the door sweeps from fresh air through to defrost. DTC B1271 is set when the climate control module detects the wiper feedback voltage staying at or near 0V in a manner consistent with the signal wire being shorted directly to chassis grou...

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