OBD-II code · Body
B0840 Left Rear Turn Signal Circuit
A fault has been detected in the left rear turn signal circuit.
Is it safe to drive with B0840?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyBurnt out turn signal bulb
Symptoms
- Warning light or symbol related to the affected system
- Comfort or safety function impaired
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.2–1 h
- Emissions test
- Usually unaffected
- Parts involved
- Left Rear Turn Signal, Body Control Module
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.