MIL ON - Poor Driveability/Multiple Misfire DTC's Set
Group 12Engine
Electrical Systems
12 02 97
Woodcliff Lake, NJ
Service Engineering
April 2001
This Service Information bulletins supersedes S.I. 12 02 97 dated January 2001.
SUBJECT
M52, M52TU/S52 Misfire Faults
MODEL
E36 - Z3, 323i and 328i with M52 engine and M3 with S52 engine
E46 - 323i, 328i with M52TU engine
E39 - 528i with M52, M521U engine
COMPLAINT:
Customer complaint that the "Check Engine" lamp is illuminated and:
-- Fault Codes 238 (EE hex), 239 (FF hex), 240 (FO hex), 241 (F1 hex), 242 (F2 hex), or 243 (F3 hex) are set in the Engine Control Module (ECM/[1][2]DME)
Other customer complaints may include: vehicle runs rough, is down on power, exhibits poor starting, etc. (see "Cause" section below for further possible sources of misfire faults).
CAUSE
A misfire fault(s) will set if:
-- the total misfire count of one or more cylinder(s) exceeds a predetermined value of misfires per 1000 engine revolutions.
The check engine light will be illuminated:
-- if a particular misfire fault is set for the second time after exceeding a predetermined value of misfires per 1000 engine revolutions.
-- immediately if the total count exceeds a predetermined value of misfires per 200 engine revolutions.
The [1][2]DME obtains its cylinder reference information from the Crankshaft Position Sensor. If the signal is implausible an erroneous reference mark can be obtained by the DME which will result in a misfire fault being set.
Possible causes of cylinder misfire faults (items identified by * indicate actual field findings):
-- *Vehicle ran low or out of fuel
-- *Poor fuel quality (ex. water in fuel, customer uses an additive, etc.)
-- Low/high fuel pressure
-- *Ignition coil
-- *Injector harness connector loose (X6150)
-- *Fouled spark plug(s)
-- *Restricted / contaminated fuel injector(s)
-- *Crankshaft position sensor
-- Poor combustion due to low compression or high leakage
-- *Broken valve spring
-- *Engine over-rev
-- *Hydraulic bucket tappet (HVA) binding. Note: A common complaint associated with a binding HVA element is that the engine runs rough during the warm up phase.
CORRECTION
Updated programming software was introduced into production as of 4/97.
If there is a component/hardware failure (reproducible fault) a modified [1][2]DME program will not fix the problem.
Whenever possible it is important to try and operate the vehicle under the same conditions at which the fault occurred.
1. If fault is reproducible,
2. Look for a hardware/component failure.
3. Vehicles produced 10/95-4/97 should be reprogrammed using the MODIC or
DIS
programming version P23.0 or higher (Follow the programming procedure in section B).
PROCEDURE
Whenever possible it is important to try and operate the vehicle under the same conditions at which the fault occurred.
Example: Misfire fault occurred at 2000 RPM
Test/Evaluate: Operate the vehicle at 2000 RPM
under various load conditions to
determine if fault will reset.
1. Determine if a fault is reproducible:
-- Follow the M52 Misfire Faults troubleshooting procedure (Flow Chart)
Note:
Misfire diagnosis information for all models can also be found in the
Emissions Overview training handout, course number ST055. (See "Misfire Diagnosis" section of the handout).
2. If the fault is no longer reproducible and the production date of the vehicle is 10/95-4/97 the [1][2]DME should be reprogrammed.
Vehicles produced up to 4/97 that have not been reprogrammed may have one of the following part numbers for a "Programmed control unit" displayed on the [1][2]DME identification screen of the DIS.
If one of these numbers is displayed the control module must be reprogrammed as shown.
WARRANTY INFORMATION
Parts and labor will be reimbursable under the terms of the applicable BMW New Vehicle Limited Warranty or BMW Emissions Warranty.