Basic checks
Veepeak OBDCheck BLE
A Bluetooth LE adapter for reading standard engine codes and supported live data.
View on AmazonB0339
Rear Seat Heater Circuit
Moderate severity
The body control module has detected a fault in the rear seat heater circuit. The rear heating elements are open or shorted.
The body control module has detected a fault in the rear seat heater circuit. The rear heating elements are open or shorted.
Common causes
- high
Heater element broken
One of the most commonly reported causes for this code — check this first.
Typical part cost: $170-880
- medium
Wiring open under seat
A plausible cause — test and verify before replacing parts.
Typical part cost: $170-880
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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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Tools you may need
Already have a compatible scanner? Use it. If not, a Bluetooth OBD2 adapter can help you confirm engine codes and check supported live sensor data before replacing parts.
Regular diagnostics
vgate iCar Pro BLE 4.0
A Bluetooth LE adapter with an automatic sleep feature for routine code and sensor checks.
View on AmazonAnother option
OBDLink CX
A Bluetooth LE adapter to consider when comparing supported vehicles and diagnostic apps.
View on AmazonIllustrations shown, not product photos. Check vehicle, phone and app compatibility before buying. These adapters do not guarantee access to ABS, airbags or manufacturer-specific systems. Clearing a code does not repair the fault and can reset emissions readiness monitors.
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Related codes
See related trouble codes
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Frequently asked questions
What does B0339 mean?
B0339 means "Rear Seat Heater Circuit". It is a generic OBD-II code that points to a fault in the body.
What are the most common causes of B0339?
heater element broken; wiring open under seat — 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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