Fuel/Engine Controls - DTC's Set/Hard Start/Driveability: Overview
SI B12 55 06Engine Electrical Systems
January 2011
Technical Service
This Service Information bulletin supersedes SI B12 55 06 dated December 2010.
[NEW]designates changes to this revision
SUBJECT
N54 - Diagnosis for DME FC 29DC/29F2/2FBF
MODEL
E90, E92 with N54 produced from 06/06
E93, E60, E61 with N54 produced from 03/07
E82, E88 with N54 from start of production
E71 X6 with N54 from start of production
E89, Z4 with N54 from start of production
F01, F02 with N54 from start of production
SITUATION I
The customer may complain of:
^ Excessive cranking time before the engine starts (5-6 seconds) on a cold start or afier a hot soak.
In most cases, diagnosis shows fault code 2FBF as the only fault stored in the DME with SES lamp illumination.
SITUATION II
The customer may complain of the following:
^ "Vehicle loses power while driving" or "Vehicle runs poorly".
^ The Service Engine Soon lamp may be illuminated.
Diagnosis shows fault code 29DC (Cylinder injection cut-out, pressure too low in high-pressure system) and/or 2FBF (Fuel pressure on-release injection, pressure too low), and in some cases, also in conjunction with 29F1 (Fuel high-pressure, plausibility) and 29F2 (Fuel high-pressure, fuel pressure undershot).
In some cases, misfire faults for various cylinders (e.g., FC 20D1, 29CF, 29D2, 29CE, 29D0, 29CC) are also stored in MSD80/M5D81.
CAUSE
Possible causes may include:
^ Sensitivity of injection pump (HDP) diagnostic software
^ Internal failure of a High-pressure Injection Pump (HDP)
^ Failure of an electric fuel pump or a clogged fuel filter
^ Failure of the low or high-pressure sensors
^ Defective fuel pressure check - valve/fuel pressure regulator
^ Failure of a volume control valve
^ Defective fuel injector
^ Intermittent electrical connection problem (wire and/or connector) in the fuel delivery system.
PARTS INFORMATION
WARRANTY INFORMATION
ATTACHMENTS
B125506_N54_ENGINE DIAGNOSTIC_FAULT_TREE_01_06_11