BMW DTC P306D – Fuel Supply Closed Loop Fuel Control, Upper Limit Exceeded
DTC P306D meaning on BMW
DTC P306D for BMW indicates that the fuel supply closed-loop fuel control system has detected that the upper limit has been exceeded. This means that the engine control module (ECM) is receiving a signal indicating that the fuel mixture is too rich, potentially leading to issues with fuel efficiency and emissions.
BMW DTC P306D symptoms
Symptoms of DTC P306D on a BMW may include decreased fuel efficiency, rough idling, engine misfires, hesitation during acceleration, and potentially an illuminated check engine light on the dashboard.
BMW DTC P306D causes
The causes of DTC P306D on a BMW can vary, but common culprits include a faulty oxygen sensor, a malfunctioning fuel injector, a vacuum leak, issues with the fuel pressure regulator, or a problem with the ECM itself.
BMW DTC P306D seriousness
While DTC P306D may not cause immediate drivability issues, it can lead to decreased fuel efficiency and increased emissions. Ignoring this fault code can potentially cause damage to the catalytic converter over time and may result in a failed emissions test.
How to diagnose DTC P306D on BMW
To diagnose DTC P306D on a BMW, a mechanic would typically use a diagnostic scanner to retrieve the fault code and then perform further testing to pinpoint the exact cause. This may involve checking the oxygen sensor, fuel injectors, vacuum lines, and fuel pressure regulator for any faults.
How to fix DTC P306D on BMW
Fixing DTC P306D on a BMW usually involves addressing the underlying cause of the rich fuel mixture. This could include replacing a faulty oxygen sensor, repairing a vacuum leak, cleaning or replacing a clogged fuel injector, or addressing any other component that may be contributing to the issue.
How to erase DTC P306D on BMW
Once the underlying issue causing DTC P306D on a BMW has been fixed, the fault code can be cleared using a diagnostic scanner. This will reset the ECM’s memory and turn off the check engine light. It is important to ensure that the issue has been properly addressed before clearing the fault code.
Recommended tools & DTC Scanners for BMW
Best Diagnostic App for modern BMWs: BimmerLink
Recommended Bluetooth adapter for Bimmerlink: OBDLink CX
Cable adapter for Bimmerlink: Enet Cable USB Type C
For older BMWs we recommend: Autel AutoLink AL319 (2024 version)
Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter
Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.