HIGH
System: Ignition & Misfire System
SAE J2012 Standard
P0306: Cylinder 6 Misfire Detected
The ECM detects crankshaft speed drop on Cylinder #6.
Driveability & Safety Advisory
Drive short distances only.
Official Manufacturer TSB Advisories
BMW SIB 12-02-12
Target: 2007–2013 BMW 335i / 535i (3.0L N54/N55)
Factory Condition: Cylinder 6 ignition coil overheats due to tight packaging near firewall under microfilter cowl.
OEM Service Remedy: Replace Cylinder 6 ignition coil with updated Bosch/Delphi coil and install heat shielding.
Physical Component Location & Service Access
Rearmost cylinder on Inline-6 engines (BMW), or middle/rear cylinder on V6 engines.
Electrical Specifications & Live PID Benchmarks
Scan Tool Live Data Targets
Cylinder 6 Misfire:
Active counts
Digital Multimeter (DMM) Specs
Coil Resistance:
0.8 – 1.3 Ohms
Documented Model-Specific Case Studies
2008–2012 BMW 335i
Root Cause: Cylinder 6 coil failed from exhaust heat.
Verified Fix: Replace coil.
Technician Inspection & Testing Workflow
1
Swap coil with Cylinder 1.
2
Check spark plug condition.
3
Check injector.
Cost Breakdown
DIY Replacement Parts:
$35 – $95
Independent Repair Shop (Parts + Labor):
$180 – $380
Standard Diagnostic Time:
1.0 – 2.0 Flat-Rate Hours
Tools & Parts Matrix
Recommended Parts:
Ignition coil, Spark plug
Required Test Tools:
Ratchet set, OBD2 scanner
Diagnostic Questions & Answers
Why does Cylinder 6 fail most frequently on BMW inline-6 engines?
Cylinder 6 is packed tightly against the firewall under the cabin filter cowl, where heat dissipation is poorest, causing thermal degradation of the coil.