Code Definition

B1000 — Headlamp range adjustment control module supply voltage low

System: Body  |  Type: Manufacturer-Specific  |  Make: Mercedes-Benz

About B1000

B1000 is a manufacturer-specific body diagnostic trouble code recorded for Mercedes-Benz vehicles. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1000 is stored, the module has detected a signal or supply voltage lower than the expected operating range; and a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour.

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.

B1000 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

Mercedes-Benz vehicles equipped with automatic headlamp range adjustment (sometimes called LWR) use a dedicated control module that drives the headlamp levelling motors based on ride-height sensor data and vehicle load. DTC B1000 is set when this control module detects that its own battery supply voltage has fallen below the minimum operating threshold (typically around 9 volts) for a calibrated period of time. A low supply can cause the headlamp levelling system to enter a fault state, default to a fail-safe aimed-down position, or become completely inoperative. The driver may see a headlamp ...

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