Code Definition

B1299 — Power Supply Sensor Circuit Short To Ground

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

About B1299

B1299 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 B1299 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit; 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.

B1299 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 Body Control Module (BCM) monitors a power supply sensor circuit that reports the voltage at a key power feed, typically the main battery voltage rail or a downstream switched supply, so the module can make informed decisions about charging system requests, load shedding, and accessory enable timing. DTC B1299 sets when the BCM detects the sense voltage on this input has fallen below the lower plausibility threshold, indicating the signal wire is shorted to chassis ground rather than reading the intended sense point. The sense input is normally a high impedance analogue pin that should tra...

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