Ignition System - MIL ON/Misfire DTC's Set

SI B 12 21 06
Engine Electrical Systems

October 2006
Technical Service

This Service Information bulletin supersedes S.M. B12 201 03 dated July 2005.

SUBJECT
Spark Plug Cracked

MODEL
E46, 323i with M52TU up to 03/00

SITUATION
Check engine light is illuminated and misfire faults with cylinder injection cutout stored in DME module. Vertical crack found in spark plug porcelain insulation.

CAUSE
Insulation failure in spark plug extension socket.

PROCEDURE
When the above-mentioned fault is encountered, on a customer complaint basis, replace cracked spark plug (NGK plug PN 12 12 9 071 003 or Bosch plug PN 12 12 0 141 871) together with a defective spark plug extension socket (PN 12 13 9 067 831).

Important:
Replacing cracked spark plug only will not prevent fault from reoccurring.

WARRANTY INFORMATION
For information only.





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