While driving in stop and go traffic I heard a loud popping noise from the dash area and smoke started filling the cabin. I called a DC area dealer service dept and was told to exit the DC beltway and un plug the audio amplifier in the trunk left access door That stopped the popping noise and the smoke .
2014 Mercedes-Benz E-Class electrical problems
severe Owners of the 2014 Mercedes-Benz E-Class have filed 35 NHTSA complaints about the electrical, typically surfacing around 47,200 miles at roughly $850 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See electrical across all vehicles →
Failure mileage
Complaints
35
Recalls
0
Avg fix
$850
| Model year | electrical complaints |
|---|---|
| 2010 E-Class | 12 |
| 2011 E-Class | 7 |
| 2012 E-Class | 14 |
| 2013 E-Class | 12 |
| 2014 E-Class (this page) | 35 |
| 2015 E-Class | 4 |
| 2016 E-Class | 8 |
| 2017 E-Class | 22 |
| 2018 E-Class | 11 |
1crash
10fires
When does it fail?
Of the 35 electrical complaints filed for the 2014 Mercedes-Benz E-Class, here's the actual mileage breakdown — failures cluster heaviest at 50,000-75,000 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 stands out
Of the 18 model years of Mercedes-Benz E-Class we track for electrical problems, this one carries the most owner complaints on file — 35.
Owners have filed 35 electrical complaints with NHTSA against this vehicle, but no formal recall covers the issue — the federal record reflects what manufacturers have admitted, not everything owners are reporting.
The failure pattern owners describe
The most serious and recurring complaint is fire in the Harmon Kardon audio system. Multiple owners report crackling or popping sounds from speakers, followed by a burning plastic smell and heavy smoke filling the cabin—often while driving at highway speeds. Speaker components melt; one mechanic suffered second-degree burns from touching an overheated speaker. The issue stems from an internal short in the amplifier. Owners document replacement costs of $400 per speaker and $2,700 for the amplifier, yet Mercedes-Benz has issued no recall despite complaints dating back to 2016 across owner forums. Many out-of-warranty vehicles are denied coverage.
Beyond the audio system, owners report sudden and complete loss of throttle response during acceleration on highways, forcing them to coast across multiple lanes to safety while multiple warning lights illuminate. Other owners describe simultaneous failures of power steering, brakes, lane-keep assist, and other electrical systems lasting 45-60 seconds before resolving on their own. Dealers often cannot diagnose these intermittent glitches.
Additional failures include trunk latches that open randomly during driving, a faulty radar sensor causing speed-gauge errors, and a camshaft solenoid valve short in the engine bay. One owner's ignition switch module failed mid-cruise, causing a stall. The contaminated electrical harness from leaking camshaft sensors poses risk of engine shutdown at critical moments.
Same Mercedes-Benz E-Class electrical reports on nearby years: 2012 · 2013 · 2017
Failure modes owners describe
Harmon Kardon amplifier and speaker system fire
Audio amplifier develops an internal short circuit, causing overheating that melts speakers and ignites electrical fires inside the vehicle. The failure produces crackling or popping noises, burning plastic odor, and heavy smoke in the cabin. Fires can occur while driving at highway speeds with no warning. Multiple speakers across different locations (front dashboard, rear deck, door panels) are affected across many vehicles.
When: Occurs at various mileages from under 40,000 to over 87,000 miles; some owners report it happens multiple times over months or years
Symptoms owners cite: Crackling, popping, or sputtering sounds from one or more speakers; Smell of burning plastic or electrical fire; Smoke or heavy smoke filling cabin; Sounds continue even when radio is off or audio system is disabled; Speaker components appear melted or damaged; Second degree burns reported when mechanic touched hot speaker
Codes mentioned: Control Module TYP Sirius SDAR
Repairs/costs cited: Owners cite replacement costs of $400+ per speaker and $2,700+ for amplifier replacement. Some dealers have successfully identified and replaced burnt amplifier units and damaged speakers, but repairs are often denied as out-of-warranty. Disconnecting audio system fuses stops the problem.
Recalls/TSBs owners mention: No recalls issued despite numerous documented complaints dating back to 2016 on owner forums. Mercedes-Benz has reportedly claimed they were not aware of the problem or do not recognize it as a safety issue. Out-of-warranty vehicles are often denied coverage.
Sudden loss of throttle response and engine shutdown under acceleration
Vehicle experiences complete and sudden loss of engine power during heavy acceleration on the highway, accompanied by multiple dashboard warning lights (Pre-Safe Functions Limited, Check Engine) and complete unresponsiveness of the accelerator pedal. Engine appears to shut off with no audible stall. Condition resolves only by shifting to Park, pressing the ignition button as if turning off, waiting, and restarting.
When: Occurs during highway acceleration; one owner reported two instances within 60 days
Symptoms owners cite: 100% unresponsive accelerator pedal during heavy acceleration; Engine cuts power mid-acceleration; Multiple warning lights illuminate on dashboard including 'Pre-Safe Functions Limited'; Engine appears already off before driver shifts to Park; Total loss of speed control forcing driver to coast to shoulder across multiple lanes
Codes mentioned: Pre-Safe Functions Limited
Repairs/costs cited: Owners note the issue resolves after restart with no permanent damage; described as a software or electronic glitch. No repair attempts are documented in the narratives.
Recalls/TSBs owners mention: No manufacturer response documented. Owner notes similar issues reported on Mercedes-focused blogs suggesting this affects other Mercedes models.
Contaminated electrical harness due to camshaft sensor oil seepage
Oil from the upper camshaft position sensors seeps into the engine electrical harness, contaminating the wiring and potentially reaching the engine control unit (ECU). This causes fault lights and performance issues, and poses risk of engine shutdown or incorrect engine timing at critical moments.
When: Manifests as fault codes and performance loss; one documented at 54,000 miles
Symptoms owners cite: Fault lights on dashboard; Multiple performance issues; Engine may shut down without warning; Risk of incorrect engine timing leading to incorrect detonation
Codes mentioned: Oil contamination in engine harness
Repairs/costs cited: Requires replacement of contaminated electrical harness on engine. Described as a 'known issue' by dealer.
Recalls/TSBs owners mention: Dealers acknowledge this as a known manufacturing issue; no recall information provided in narratives.
Push-to-start button electrical failure
Push-to-start ignition button fails to operate, forcing the owner to use the key fob to start the vehicle. After the failure, the vehicle also fails to start with the key fob, rendering the vehicle essentially unstarrable. Dealer diagnoses an electrical failure but declares it unrepairable.
When: Failure mileage unknown
Symptoms owners cite: Push-to-start button stops responding; Vehicle requires key fob activation as workaround; Key fob start subsequently fails as well
Repairs/costs cited: Dealer reported the failure as unrepairable. Vehicle was not repaired.
Recalls/TSBs owners mention: No manufacturer notification or response documented.
Trunk latch fails and opens randomly during driving and parking
Trunk latch mechanism fails and pops open intermittently without warning, occurring during motion at various speeds, while parked, in different weather conditions, and regardless of gear or engine state. Owner documented 6-8 occurrences within 5,000 miles of ownership despite two repair attempts.
When: Begins within 5,000 miles of ownership; persists for at least 8+ months despite repairs
Symptoms owners cite: Trunk opens without driver input via key fob or door-mounted release; Occurs at speeds from 40-50 mph down to crawling speed; Occurs while in motion, at stop, in any gear, parked with engine running; Occurs in both cool and warm temperatures; Occurs with top up or down (convertible)
Repairs/costs cited: Two documented repair attempts; defect persists. Dealer has been unable to resolve the issue.
Recalls/TSBs owners mention: No manufacturer response documented.
Radar sensor failure causing multiple system malfunctions
Faulty rear bumper radar sensor causes intermittent failure of multiple electrical safety systems including lane keep assist and ABS braking. When the sensor fails, the instrument cluster speed display rapidly changes speeds, making actual vehicle speed unknowable to the driver—a critical hazard when driving in traffic.
When: Occurs intermittently at random while driving
Symptoms owners cite: Lane keep assist fails; ABS system fails; Instrument cluster speed reading rapidly fluctuates and becomes unreliable; Random occurrence during normal driving
Codes mentioned: Faulty Radar Sensor in rear bumper
Repairs/costs cited: Part is on backorder with no sign of urgency from Mercedes-Benz.
Recalls/TSBs owners mention: None documented; parts remain backordered as of complaint submission.
Camshaft position solenoid valve short circuit and ignition fuse failure
Camshaft position solenoid valve develops a short circuit causing the ignition fuse to blow and cascading mechanical problems. The faulty part is mounted in a high-heat location in the engine compartment, posing fire hazard risk to occupants.
When: Occurred at unspecified mileage during secondary road driving
Symptoms owners cite: Engine sputtering and severe misfiring at idle; Check engine light illumination; Engine entering limp mode at dangerous location (railroad crossing); Loss of acceleration capability
Codes mentioned: Check Engine Light
Repairs/costs cited: Required replacement of camshaft position solenoid valve and ignition coil. Repair cost documented at $1,100.
Intermittent multiple electrical system failures with instrument cluster malfunction
During highway driving, multiple electrical and safety systems fail simultaneously: steering, braking, lane keep assist, ABS, Pre-Safe functions, and SRS. Warning lights flash continuously and instrument gauges (temperature, RPM) move erratically. Normal operation resumes after 45-60 seconds or upon restart.
When: Occurs intermittently; one owner reported 5 separate occasions
Symptoms owners cite: Power steering stops working; Brakes fail; Lane keep assist inoperative; Active blind spot assist inoperative; Histronic Plus system inoperative (likely 'Distronic Plus' adaptive cruise); Pre-Safe functions fail; SRS malfunction; Instrument cluster warning lights flash rapidly; Temp gauge and RPM gauge pointer movement becomes erratic; Cruise control stops working
Codes mentioned: Active Lane Keeping Assist Inoperative, Active Blind Spot Assist Inoperative, Pre-Safe Inoperative, Power Steering Malfunction
Repairs/costs cited: Multiple dealer diagnostic attempts have found nothing wrong. One instance cost $1,100 related to power steering. No permanent repairs made.
Collision Prevention Assist false positive warnings
Advanced driver assistance system generates false warning indicators and audible alerts when passing vehicles in the adjacent left lane during normal highway driving in traffic. System activates with no actual collision threat, creating driver distraction and false sense of danger.
When: Occurs at least twice per month during heavy traffic driving
Symptoms owners cite: Dashboard indicator lights illuminate for collision threat; Audible warning beeps sound; Warnings occur only during normal lane passing maneuvers; No actual collision threat present
Repairs/costs cited: System can be disabled but reactivates every time the vehicle is started.
Recalls/TSBs owners mention: Dealer tested system and found it within specifications; no remedy offered.
Ignition switch assembly module failure
Ignition switch assembly module fails, causing the vehicle to stall without warning. Driver experiences intermittent beeping for several minutes before the vehicle stalls.
When: Occurred during cruise at unspecified speed
Symptoms owners cite: Intermittent beeping sounds from ignition system for several minutes; Vehicle stalls unexpectedly; Complete loss of engine operation
Repairs/costs cited: Ignition switch assembly module requires replacement.
Recalls/TSBs owners mention: Dealership refused to repair the vehicle despite initial towing, which owner notes as suspicious and potentially an attempt to avoid documenting the problem.
Climate control temperature inconsistency
Heating system fails to maintain set temperature. When driver sets temperature to 80°F, the system initially blows hot air but after 10 seconds switches to blowing cold air. Driver must set temperature to maximum to achieve consistent hot air output.
When: Ongoing issue with no mileage specified
Symptoms owners cite: Temperature fluctuates between hot and cold at set thermostat value; System defaults to cycling cold after initial heat
Synthesized from 35 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 3 most recent
The heater temperature is not consistent and keeps fluctuating. When I set the temperature to 80°F, it initially blows hot air, but after about 10 seconds, it starts blowing colder air. To get consistently hot air, I have to set the temperature to the maximum.
I was driving on route 40 (speed limit 55mph, but 45 MPH due to construction) when I began hearing rattling in my rear passenger side speaker, then crackling, a burning smell and then smoke filled my vehicle. I believed my vehicle was on fire. Had I not remained calm, I could have caused an accident. I ended up driving to a nearby walmart parking lot where I left my vehicle until it was towed to…
Had electrical trouble with your 2014 Mercedes-Benz E-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 2014 Mercedes-Benz E-Class?
It's a meaningful issue. 35 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $850.
At what mileage does the electrical typically fail?
Across the 19 complaints that reported odometer mileage, most electrical failures cluster between 30,509 and 60,500 miles, with the median around 47,200. A quarter of owners report trouble before 30,509; a quarter make it past 60,500. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
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/2014/Mercedes-Benz/E-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.