My 2015 Mercedes-Benz GL63 AMG has suffered two separate ECU failures caused by oil migrating through the engine wiring harness. The first failure occurred at ~42,600 miles in 2020, and the second at ~59,000 miles in 2023. Both times, the vehicle developed misfires, check-engine warnings, and drivability issues that could have led to stalling at highway speeds. On both occasions, the vehicle has…
2015 Mercedes-Benz GL-Class electrical problems
moderate 4 complaints filed with NHTSA · avg repair $850 · see electrical across all vehicles →
Complaints
4
Recalls
0
Avg fix
$850
When does it fail?
Of the 4 electrical complaints filed for the 2015 Mercedes-Benz GL-Class, here's the actual mileage breakdown — failures cluster heaviest at 25,000-50,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What owners are reporting 3 most recent
The vehicle misfired while driving on city streets and presented a code for faulty ignition coils. Upon inspection, Mercedes-benz service center found oil in the engine wiring harness rendering the car undriveable.
Tl* the contact owns a 2015 Mercedes-benz gl450. While driving 40 MPH, the vehicle stalled and the pre-safety function limited warning indicator illuminated. The vehicle was pushed over to the side of the road by the contact and passenger. The contact attempted to restart the vehicle, but it failed to start. The vehicle was towed to Mercedes-benz of arcadia (101 n santa anita ave, arcadia, ca…
Had electrical trouble with your 2015 Mercedes-Benz GL-Class?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the electrical problem on the 2015 Mercedes-Benz GL-Class?
It's a documented issue but not catastrophic. 4 complaints have been filed. Repairs average $850 and most owners catch it before it causes a breakdown.
At what mileage does the electrical typically fail?
Based on the 4 complaints filed, electrical issues most often appear around 33,500 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $850 for electrical repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to electrical?
No active recalls currently cover electrical issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2015/Mercedes-Benz/GL-Class.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.