Fuel System - MIL ON/Misfire DTC's Set/Hard Hot Starting
Date: December 10, 2004Order No.: P-B-47.20/31
Supersedes:
Group: 47
SUBJECT:
Model 215.376 Model 220.176 Model 230.476 with Engine M275
Hot Start Performance Complaints with Winter Fuel Which Contains Ethanol
If you receive customer reports in the above model vehicles of hot start performance complaints, mainly in areas where winter fuel contains ethanol, proceed as follows to resolve.
Note:
This applies only to vehicles with the check engine light activated and misfire codes on the front cylinders (i.e. cylinder number 1, 2, 7, 8) where the freeze frame data indicates that the misfire was detected immediately (up to 1 minute) after engine restart at operating temperature (Figure 2). All other cases, proceed as outlined in V12 Engine Complaints Diagnostic Tree located on STAR TekInfo (EDAC).
1. Print all stored fault codes with freeze frame data from the ME engine control unit.
2. Check and analyze freeze frame data based on the description of the symptoms (Figure 2).
^ If freeze frame data (Figure 2) does not indicate hot start issue, proceed as outlined in V12 Engine Complaints Diagnostic Tree located on STAR Teklnfo (EDAC).
^ If freeze frame data (Figure 2) indicates hot start issue, continue with step 3.
3. Check fuel pressure and fuel delivery of component M3 (fuel pump) as described in DAS. Perform repairs as necessary.
4. Check fuel pressure at rest as described in DAS version 11/2004 or later (Figure 1).
5. Monitor the pressure at rest 40 minutes after engine shut down (engine must have working pressure within specifications before shut down).
Note:
It is only after 40 minutes that the technician checks the pressure at rest. However, the vehicle must remain at the same temperature condition as started in the workshop (room temperature).
6. If the specified value for the fuel pressure at rest is below the specified value of 2.6 bar, proceed with installation of the following parts.
Refer to the following applicable WIS documents:
7. After the installation of the fuel filter and fuel pump is completed, insure that the fuel system is properly bled.
8. Check the specified value for the modified working pressure [4.7... 5.3 bar] and shut the engine off when engine operating temperature (coolant temperature > 90 degree Celsius) is reached.
9. Restart hot engine after 40 minutes.
Note:
As a precaution, insure secondary coolant system is properly bled, refer to WIS document AR20.00-P-1145H.
Note:
All fuel pump control units exchanged under warranty for the above condition must be accompanied by the printout of all fault codes stored in the ME engine control unit and freeze frame data showing the symptoms (Figure 2) of a hot start performance problem. Claims submitted without this information as of repair date December 13, 2004 will be debited back to the dealer.
Parts Information
Note:
The following allowable labor operations should be used when submitting a warranty claim for this repair.
In Case of Warranty