B0240

Headlamp Switch Circuit

Moderate severity

The body control module has detected an implausible state at the headlamp switch — for example simultaneous low and high beam request, or no signal at all. Lighting functions may be erratic.

Common causes

Headlamp switch worn or failed
One of the most commonly reported causes for this code — check this first.
high
Typical part cost: $60-440
Wiring or connector fault
A plausible cause — test and verify before replacing parts.
medium
Typical part cost: $60-440
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First things to check

1Confirm the code with a scan tool and check for additional related codes.
2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.

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Related codes

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Frequently asked questions

What does B0240 mean?

B0240 means "Headlamp Switch Circuit". It is a generic OBD-II code that points to a fault in the body.

What are the most common causes of B0240?

headlamp switch worn or failed; wiring or connector fault — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.

Can I keep driving with this code?

The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.

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