Table of Contents
Diagnosing and Fixing the Engine Is Shaking Issue in a Mercedes-Benz GLE 350
Few things are more unsettling for Mercedes-Benz owners than starting the car and feeling the engine shake. This problem not only reduces driving comfort but can also affect performance, fuel efficiency, and long-term engine health.
In this case study, we examine a Mercedes-Benz GLE 350 equipped with the M264 Engine. The vehicle was brought into the workshop with the complaint of an engine that shook while running and a check engine light on the dashboard. Interestingly, once the engine was shut off, everything appeared normal.
This article will walk through the diagnostic steps, findings, and final repair solution. It also provides practical takeaways for technicians and owners dealing with similar issues.
Initial Customer Complaint
The customer described the issue as follows:
- => The engine shakes when running.
- => The check engine light remains on.
- => After turning the engine off, no visible issues are noticeable.
Step-by-Step Diagnostic Process
1. Reading Fault Codes
The first step was to connect the vehicle to the Mercedes-Benz Xentry diagnostic system and read fault codes stored in the Motor Electronics (ME) control unit.
- – Findings: Multiple fault codes related to cylinder misfires were logged.
- – Action: These codes confirmed that a deeper diagnostic process was necessary.
2. Checking for Software Updates
Modern Mercedes engines rely heavily on control unit software.
- – Step: Checked the ME control unit for available software updates.
- – Findings: A newer version was available.
- – Action: Updated the control unit software, cleared fault codes, and re-ran diagnostics.
- – Result: At this stage, no codes reappeared.
3. Analyzing Smooth Running and Cylinder Fault Counters
To pinpoint the misfire, the next step was to analyze live data values:
- – Cylinder #2 showed irregular smooth running values.
- – Fault counters indicated repeated misfires in this cylinder.
This narrowed the investigation to cylinder-specific issues rather than a general engine fault.
In-Depth Component Inspection
4. Checking Cylinder #2 Components
Spark Plug Inspection:
- – The spark plug for cylinder #2 was in good condition, ruling it out as the primary cause.
Ignition Coil Swap Test:
- – The ignition coil from cylinder #2 was swapped with cylinder #3.
- – After the swap, misfires still occurred in cylinder #2, but intermittent misfires also began in other cylinders.
This suggested the issue was not isolated to the ignition coil or spark plug.
5. Decision to Replace Injectors
Given the persistent irregularities and spreading misfire symptoms, attention shifted to the fuel injectors.
- – Action Taken: All injectors and their seal rings were replaced to ensure balanced fuel delivery across cylinders.
- – Rationale: Replacing all injectors prevents partial fixes and ensures consistent engine performance.
Remedy and Resolution
Replacement Process
- – Removed and replaced all four injectors along with seal rings.
- – Recalibrated the engine system post-installation.
Final Test Drive
- – Conducted a road test to confirm smooth running.
- – Result: The engine shaking issue was resolved.
- – No fault codes reappeared in the ME control unit.
- – Engine smooth running values returned to normal.
Symptom – Cause – Fix Table
| Symptom | Likely Cause | Fix |
|---|---|---|
| Engine shakes at idle or low RPM | Misfire in one or more cylinders | Read fault codes, analyze smooth running values |
| Check engine light + shaking | Ignition coil or injector failure | Swap coils, test injectors, replace faulty parts |
| Misfire isolated to one cylinder | Faulty spark plug or injector | Replace spark plug, inspect coil, replace injector |
| Misfires spreading to multiple cylinders | Fuel injector set imbalance | Replace all injectors and recalibrate |
| Shaking stops when engine is off | ECU misfire detection only when running | Perform diagnostic scan and update ECU software |
Explore More Mercedes Engine Misfire Issues
For a deeper dive into all misfire-related problems, visit our hub page: Mercedes Engine Misfire Issues – Causes and Fixes. You’ll find grouped case studies, step-by-step diagnostics, symptom–cause–fix tables, and prevention tips to help you resolve misfire problems quickly and effectively.
Key Takeaways for Technicians and Owners
1. Use Diagnostic Tools Effectively
- – Always begin with fault code reading.
- – Confirm if a software update is available for the ME control unit.
2. Analyze Actual Values
- – Smooth running and cylinder fault counters are essential for identifying problem cylinders.
3. Component Swapping for Accuracy
- – Swap coils or plugs between cylinders to rule out isolated component faults.
4. Think Beyond the Basics
- – When misfires persist across multiple cylinders, fuel injectors are a strong suspect.
5. Verify Repairs Thoroughly
- – A final test drive combined with a fault code scan is essential before confirming resolution.
FAQs on Mercedes Engine Shaking Issues
Q1: Why does my Mercedes engine shake at idle?
Shaking is usually caused by a misfire. Common culprits include spark plugs, ignition coils, or fuel injectors.
Q2: Can I drive my GLE 350 if the engine is shaking?
It’s not recommended. Driving with misfires can damage the catalytic converter and reduce engine lifespan.
Q3: How much does it cost to fix engine shaking?
Costs vary: spark plugs (€100–€200), ignition coils (€200–€400), injectors (€800–€1200 for a set), depending on labor and parts.
Q4: Do software updates really fix engine shaking?
Sometimes yes. Control unit updates can correct misfire detection errors or adjust fuel/ignition parameters.
Q5: Is it always necessary to replace all injectors?
Not always, but replacing all injectors ensures balanced fuel delivery and prevents repeat misfires.
Author
Written by: Mercedes Expert
Automotive Technical Trainer & Mercedes-Benz Diagnostic Specialist
With years of hands-on experience repairing and diagnosing Mercedes-Benz vehicles, specializes in case-study-based troubleshooting guides that blend workshop accuracy with educational clarity.
Last Updated: September 2025
