Code Definition

B120D (86) — Automatic Braking Malfunction – Signal Invalid

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

About B120D

B120D is a manufacturer-specific body diagnostic trouble code recorded for Peugeot 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.

B120D 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 Automatic Emergency Braking (AEB) function is supervised by the ADAS (Advanced Driver Assistance System) module. It relies on valid data from radar and/or camera sensors to detect imminent collisions and command braking intervention. DTC B120D:86 is set when the ADAS module receives invalid or implausible signals from the automatic braking system circuit, or when braking commands cannot be reliably processed. This indicates the AEB system is unavailable due to a communication or sensor fault.

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