Engine Controls, Fuel - Hard Start/Driveability/DTCs Set: Overview

SI B 12 55 06
Engine Electrical Systems

March 2010
Technical Services

This Service Information bulletin supersedes SI B12 55 06 dated March 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

SITUATION I

The customer may complain of:

^ Excessive cranking time before the engine starts (5-6 seconds) on a cold start or after a hot soak.

^ [NEW] 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/MSD81.

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.