OBD2 Car ScannerWhat does B1540 mean?
B1540 stands for Mirror Driver Switch Assembly Circuit Open. A body control module has found a fault in a comfort or safety system such as airbags, lights, doors, seats or climate control.
Body codes cover the airbags, seats, lights, doors and comfort systems. When the car's computer sees a reading outside its normal range, it stores this code and may turn on a warning light on the dashboard.
Common causes
- Damaged wiring or a loose connector (often under seats)
- Faulty switch, sensor or motor
- Low battery voltage
- Faulty body control module
What to do
- Read all stored and pending codes with a scanner. Several codes together often point to one cause.
- Note the freeze frame data (speed, temperature, load) recorded when the code was set.
- Inspect the wiring and connectors of the part named in the code for damage, corrosion or looseness.
- Fix the most likely and cheapest cause first, then clear the code and drive to see if it comes back.
Read this code from your own car
Plug in a cheap ELM327 adapter and the app shows every fault code, what it means and how to fix it.
Frequently asked questions
What does B1540 mean?
B1540 means “Mirror Driver Switch Assembly Circuit Open”. It belongs to the body system group: A body control module has found a fault in a comfort or safety system such as airbags, lights, doors, seats or climate control.
Is it safe to drive with B1540?
You can usually drive carefully for a short time, but fix it soon to avoid further damage or higher fuel use.
How do I clear B1540?
Fix the cause, then clear the code with an OBD2 scanner or app. If the fault is still there, the code will come back.
Related codes
- B1536Memory 2 Switch Circuit Open
- B1537Memory 2 Switch Circuit Short To Battery
- B1538Memory 2 Switch Circuit Short To Ground
- B1539Mirror Driver Switch Assembly Circuit Failure
- B1541Mirror Driver Switch Assembly Circuit Short To Battery
- B1542Mirror Driver Switch Assembly Circuit Short To Ground
- B1543Seat Direction Switch Assembly Circuit Failure
- B1544Seat Direction Switch Assembly Circuit Open
Code meanings can vary by manufacturer. This page is general guidance, not a repair manual. Always confirm the cause before replacing parts.