The Mercedes-Benz E320 is known for its luxurious ride and powerful engine. However, some owners have reported performance issues, prompting modifications to address these concerns. This article discusses a specific technical bulletin related to the E320 and a modification targeting engine performance and fault codes.
Understanding the Problem: Fault Codes 2511 and 2355
Model 211.026 E320s may experience limp home mode, accompanied by an illuminated check engine light. This often indicates fault codes 2511 and/or 2355 stored in the Engine Control Unit (ECU). Even without these codes, symptoms like surging, hesitation, or misfiring at part load can occur. These issues may stem from a temporarily binding EGR valve, exceeding its setpoint, triggering the fault code and limp mode. Alternatively, the ECU software itself might contribute to a lean condition under specific RPM, load, temperature, and fuel quality conditions.
The Solution: Modified EGR Valve and ECU Software Update
To rectify these problems, Mercedes-Benz issued a technical bulletin outlining a two-part solution:
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Modified EGR Valve Installation: A redesigned EGR valve (part number A646 140 19 60) is crucial to addressing the binding issue.
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ECU Software Update: A corresponding software update (patch 2005-10-13-0474 with DAS update 10/05 and later) adjusts the ECU parameters to work in conjunction with the new EGR valve. This update mitigates the potential for lean conditions and optimizes engine performance.
Important Note: The modified EGR valve and the updated ECU software must be installed together. Operating with only one component will not resolve the issue and may cause further problems.
Post-Update Procedures: SCN Coding and Injector Verification
After installing the modified EGR valve and applying the software update, two essential steps must be performed:
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SCN Coding: This process ensures proper communication and synchronization between the updated ECU and other vehicle systems. Refer to Star Tekinfo Document S-B-07.61/38g or S-B-07.00/144 for detailed SCN coding instructions.
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Injector Coding Verification: Confirm the correct coding of the fuel injectors to ensure optimal fuel delivery and engine performance. This verification prevents potential misfires or performance issues related to incorrect injector mapping.
Exploring Warranty and Assistance Options
Mercedes-Benz owners facing these issues should inquire with their dealer about potential goodwill reimbursement or coverage under the Federal 8/80 emissions warranty. If these options prove unsuccessful, contacting the Mercedes-Benz Customer Assistance Center (CAC) at 1-800-FOR-MERC is recommended to initiate a formal complaint.
Conclusion: Ensuring Optimal Performance for Your Mercedes E320
By implementing the modified EGR valve and ECU software update, along with the necessary post-update procedures, Mercedes E320 owners can effectively address engine performance issues related to fault codes 2511 and 2355. These modifications ensure a smoother, more reliable driving experience, restoring the performance expected from a Mercedes-Benz vehicle. Consulting with a qualified Mercedes-Benz technician is vital for accurate diagnosis and proper implementation of these solutions.
