BMW 29D1 identifies cylinder 5 misfire on a six-cylinder DME. An E60/early F10 N52 528i has cylinder 5; a later F10 N20/N26 528i has only four cylinders, so 29D1 on that car requires module, scanner or engine-identity verification. On a valid N52, preserve smooth-running data, inspect labeled plug/coil 5, then test injector delivery, rear intake leakage, compression and VANOS timing if the fault stays.
Match the symptom
Select the closest observation. The result changes the first test; it does not name a part to replace.
Stop loading to protect catalysts.
What can set 29D1—and how to separate it
The order below is evidence-driven, not a universal probability ranking. Vehicle year, repair history, companion codes and the operating condition in freeze frame change where diagnosis should begin.
| Possible cause | Evidence that supports it | First useful test |
|---|---|---|
| Worn/fouled plug or ignition fault | Cylinder leader and controlled swap follows | Labelled plug/ignition test |
| Injector or fuel-pressure fault | Contribution/pressure mismatch | Injector/fuel tests |
| Intake, purge or boost leak | Trim/smoke pattern | Smoke and purge test |
| Compression, valvetrain or timing fault | Count stays with mechanical weakness | Compression/leak-down/timing |
| Shared voltage or contaminated fuel | All cylinders or post-refueling | Voltage/fuel-quality test |
Count the installed cylinders first
Confirm VIN and engine. A four-cylinder F10 cannot physically misfire on cylinder 5, so do not order a fifth coil.
Read the complete module address and BMW fault text to catch stale or mistranslated data.
Test a valid N52 cylinder 5
Capture cold/load smooth-running values, inspect plug 5 and move only the suspected coil.
If the fault stays, test injector operation and smoke-test rear manifold/CCV plumbing.
Measure sealing and cam response
Use compression/leak-down and review VANOS data when fuel/ignition do not move the fault.
Verify no cylinder 5 correction or 29D1 under the original condition.
Save these scan-data clues
Freeze frame is a snapshot of conditions when the PCM matured the fault. It can distinguish an idle-only problem from a load, cold-start or monitor-completion problem. Clearing first throws that context away.
- Exact VIN, platform, model year and engine sales code
- All confirmed, pending and permanent companion codes
- RPM, load, coolant temperature and vehicle speed
- Relevant commanded and actual scan data
- Recent service, repairs and symptom conditions
- Manufacturer bulletin and current software/VIN status
A practical diagnostic workflow
- 01Identify engine and bank layout
Cylinder patterns differ.
- 02Preserve counters
Save cold/load evidence.
- 03Inspect plugs in order
Deposits direct testing.
- 04Target ignition
Use one controlled test.
- 05Test fuel and air
Graph pressure/trims and smoke paths.
- 06Prove mechanical health
Use compression/leak-down/timing.
- 07Verify original condition
Avoid a flashing-MIL road test.
Do not replace the most commonly named component from 29D1 alone. Confirm the exact engine, preserve evidence and complete the manufacturer test sequence before ordering parts.
Why the model year changes the test
The 528i badge spans E39, E60 and F10 generations. North American E60 cars generally use naturally aspirated N52 six-cylinder engines, while 2012–2016 F10 cars use turbocharged N20/N26 four-cylinders; the 2011 F10 used an inline-six. VANOS faults, boost codes, cylinder numbering, fuel pressure and crankcase ventilation therefore change by year. Decode VIN and read the engine/DME plus full ISTA text before applying a four-digit code definition.
- N52 528i has six cylinders; N20/N26 528i has four and no cylinder 5.
- Verify DME and scan profile on a four-cylinder car displaying 29D1.
- N52 injector/ignition procedures differ from N54 guidance.
- 2A82/2A87 companions raise VANOS priority.
29D1 FAQ
Does P0300 mean all coils failed?+
No.
Can I drive?+
Not with flashing MIL or strong shaking.
Can bad fuel cause it?+
Yes.
Should I replace plugs first?+
Inspect and record them first.
Can vacuum leaks cause it?+
Yes.
Can timing cause it?+
Yes, especially with cam/crank codes.
Why save counters?+
They reveal cylinder and bank structure.
What confirms repair?+
Stable counters under original conditions.
Ford diagnostic references
These documents explain Ford monitor operation. Exact pinpoint tests, connector views and specifications must be selected for the truck's VIN and model year in current service information.
01BMW Technical Information SystemOfficial VIN-, engine- and ISTA test-plan information↗02BMW owner's manualsOfficial VIN/model operating, warning and maintenance information↗