B1587 — Autolamp delay increase circuit

B1587 means: Autolamp delay increase circuit. That is the standard definition — what actually triggered it on a given car depends on the engine.

Code family

B1xxx is body systems, manufacturer-specific.

Severity

Manufacturer-specific body system — needs a brand scanner to read the actual cause.

General steps

These apply to most OBD codes and are the right starting point before replacing anything. They are not specific to this code — for that, ask me about your car below.

1. Read codes from the body control module (BCM) and the airbag module — B codes live there, not in the engine ECU.
2. Clear the code and see whether it returns at once (permanent fault) or after driving (intermittent contact).
3. Airbag/SRS: check the connectors under the seats and the clock spring in the steering wheel — the most common circuit-code sources.
4. Lighting and comfort: bulb, fuse and ground of the circuit the code names, before suspecting a module.
5. Doors, windows, locks: check the wiring boot between door and body for a broken wire.
6. Airbag codes clear only after the cause is fixed — a lit warning lamp means the system is disabled.

That is what holds for B1587 in general. From here it depends on your engine — tell me which car it is and what it does, and I will give you the steps for it: real procedures, torque figures and diagrams instead of general advice.