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A Guide to BMW Fault Codes

29/08/2025James Harding

Motoring

Modern BMWs are packed with sensors and modules. That’s good news for performance, efficiency, and safety - but it also means more warning lights and error codes.

If you’ve ever seen a “Check Engine” light or plugged in an OBD reader only to be met with cryptic numbers like P0171 or P1014, you’ll know how confusing it can feel.

BMW Fault Codes

BMW fault codes are alphanumeric codes stored by your car’s onboard diagnostics system when something isn’t working properly.

Some are generic OBD-II codes (used across all makes), while others are BMW-specific codes that require specialised scanners or software to interpret.

A fault code doesn’t always mean a part has failed - it means something isn’t behaving as expected.

How to Read BMW Fault Codes

Locate the OBD-II port (usually under the dashboard, near the steering column).
Plug in a scanner. A OBD-II reader will show generic codes. If you want detail specific to BMWs, you will need to use a scanner designed for BMWs.
Switch on the ignition (engine off).
Scan and record the codes. Some scanners will show plain-English explanations; with others, you’ll need to look up the code.
Check for multiple codes. One fault can trigger several related codes, so don’t focus on just the first one you see.

Common BMW Fault Codes

Here are some of the more common codes that a BMW owner is likely to encounter:

Fault Code	What It Means	Likely Causes	Urgency
P0300	Random/multiple cylinder misfire	Worn spark plugs, clogged injector, ignition coil	High – risk of engine damage if ignored
P0171 / P0174	System too lean (air-fuel imbalance)	Loose fuel cap, faulty O2 sensor, air leak	Medium – poor performance, long-term damage possible
P0420	Catalyst efficiency below threshold	Failing catalytic converter, exhaust issues	High – expensive if ignored, emissions fail likely
P1014	Valvetronic shaft sensor error	Electrical fault in BMW Valvetronic system	High – complex system, professional fix required
P112F	Air mass system fault	Dirty/failed MAF sensor, intake air leaks	Medium – poor economy, performance issues
P1632	Throttle valve adaptation not met	Throttle body or sensor fault, wiring	High – may cause limp mode
P0456	EVAP system leak detected	Loose fuel cap, damaged vent valve or hoses	Low to Medium – check cap first

Tip: even “minor” codes shouldn’t be ignored for long. Small problems often lead to bigger problems.

What to Do If You Get a BMW Fault Code

Check the basics first: is the fuel cap loose, or a sensor visibly disconnected?
Don’t panic: many codes are precautionary, not catastrophic.
Look for patterns: are multiple codes related to the same system? This can help to determine the main issue.
Know your limits: replacing spark plugs or air filters is DIY-friendly. Diagnosing Valvetronic or throttle faults isn’t.
If in doubt, book a diagnostic with a qualified BMW mechanic.

Can You Clear BMW Fault Codes Yourself?

Yes, but only once the problem has been fixed. Otherwise, the code will just reappear.

Ways to clear codes:

With a scanner: most OBD-II readers have a “clear/reset” function.
Using the iDrive or cluster menu: some service reminders can be reset from the dashboard.
Battery disconnect: disconnecting the battery for 15–30 minutes may reset some codes, but it’s not always reliable and can cause other issues (not recommended unless you know what you’re doing).

BMW Fault Codes – FAQs

Can I drive with a BMW fault code?

The answer is an unsatisfactory, it depends. Some codes are low-risk. Others can cause serious damage if you keep driving. If the car goes into limp mode, avoid driving until checked.

Do all BMW codes start with P?

Not always. “P” codes are standard powertrain faults. BMW has manufacturer-specific codes that may look different.

Will a service clear BMW fault codes?

A service often clears minor codes if the root cause is fixed (e.g., new filters, spark plugs). For major faults, the codes will remain until repairs are done.

What to do next

BMW fault codes can look intimidating. However, they’re just the car’s way of pointing you in the right direction. If your BMW is displaying a fault code, booking a diagnostic check or service is a good way to get the problem fixed.

At Blackcircles.com, you can find trusted garages and book online - making it easy to keep your BMW running at its best.