While I was travelling on highway, I got an alert about collision system being inoperable, I took my car to the dealership, it was investigated and was told to me that I had an accident? I did not. I am thinking it was some kind of an electrical/radar sensor issue? It did not affect my speed or ability to accelerate
2015 Mercedes-Benz C-Class electrical problems
severe 47 complaints filed with NHTSA · avg repair $850 · see electrical across all vehicles →
Failure mileage
Complaints
47
Recalls
0
Avg fix
$850
2crashes
1injury
When does it fail?
Of the 47 electrical complaints filed for the 2015 Mercedes-Benz C-Class, here's the actual mileage breakdown — failures cluster heaviest at 75,000-100,000 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
Owners have filed 47 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.
No new NHTSA electrical complaint has been filed on this vehicle in over 6 years — the issue may be aging out of the active population.
The failure pattern owners describe
Buyer takeaway: The 2015 Mercedes C-Class electrical systems are seriously unreliable. Owners report collision safety system failures that cut power without warning, entertainment screens that freeze or go dead (including the backup camera you depend on), keyless locks that trap people inside, and multiple other electrical gremlins—many occurring early in ownership with no permanent fix.
Electrical trouble plagues this generation across multiple systems. The Collision Prevention Assist Plus triggers unprompted, killing throttle response and forcing violent stops mid-drive—owners describe near-misses on highways and getting trapped mid-intersection. Restarting clears it temporarily, but it comes back. Dealers have tried radar sensor replacements, but the issue recurs; one independent shop cited a Mercedes Technical Bulletin on an electrical cable for this exact failure, yet Mercedes denies the safety concern.
The infotainment and backup camera system is unreliable. Radios freeze, Bluetooth won't pair, USB ports fail, and backup cameras display late or not at all—critical on a car you depend on for reversing. Dealerships admit hearing this from multiple owners but claim no fix exists.
Keyless entry fails both ways: vehicles lock themselves with people and pets trapped inside (one incident in 100°F heat required police intervention), and systems refuse to unlock despite the key present. The panic button doesn't work. Other owners report the system design flaw that lets anyone touch the rear door handle to unlock all doors when the key is nearby.
Less common but documented: one new car arrived with a missing plug, flooded from rain, corroded its entire electrical system—it required two electrical replacements and still malfunctioned. A recall (17V114000) for electrical/cooling issues sat unrepaired for months because parts were unavailable nationwide. Engine code P052E (faulty PCV valve) shows up across the model generation and costs $400+ plus a brutal 6-hour labor job; Mercedes hasn't recalled it despite the pattern.
Same Mercedes-Benz C-Class electrical reports on nearby years: 2012 · 2013 · 2014 · 2016 · 2017
Failure modes owners describe
Collision Prevention Assist Plus inoperative / loss of acceleration
System triggers unprompted, disables throttle response, forces sudden braking or vehicle immobilization mid-drive. Owners report violent stops in traffic, highway near-misses, and complete loss of control. Restart clears the error temporarily; issue recurs.
When: Various mileages; some reported within first year of ownership at 8k–24k miles; one at 158k miles
Symptoms owners cite: Dashboard warning: 'Collision Prevention Assist Plus Inoperative'; Accelerator unresponsive despite pedal pressure; Sudden violent deceleration; Vehicle unable to accelerate from stops; Also accompanied by ESC, Cruise Control, or Stability Control inoperative warnings
Codes mentioned: Collision Prevention Assist Plus error, Radar sensor fault (per dealer diagnostics)
Repairs/costs cited: Dealer diagnostics point to radar sensor replacement; owners report replacements were performed but issue recurred; one service advisor mentioned possible mouse damage to wiring; independent shop cited Mercedes Technical Bulletin on electrical cable replacement for acceleration/brake control issue
Recalls/TSBs owners mention: MBUSA advised customer inquiry filing; no recall issued; dealerships claim no safety issue despite multiple complaints; one Technical Bulletin issued for electrical cable replacement per independent shop
Entertainment system / COMMAND / infotainment display malfunction
Radio, backup camera, Bluetooth, USB connectivity, voice recognition, and navigation fail independently or in combination. System freezes, unresponsive to input, displays blue screen loops, or powers off. Backup camera critical safety concern for vehicle that requires it for reversing.
When: Early ownership; one at 24k miles; some "out of nowhere one day"
Symptoms owners cite: Stereo frozen or unresponsive; Backup camera does not display or activates too late; Bluetooth disabled or will not connect; Radio selection freezes all operations for ~60 seconds; USB devices will not connect; Blue screen appears briefly then loops to startup; Voice command feature disabled after recall update; Speakers cut out intermittently (hours to 5 days)
Codes mentioned: XM Radio system update (per dealer), COMMAND system software issue
Repairs/costs cited: Dealership initially attributed to XM Radio software update; temporary software update was available but issue recurred after repair; one dealership admitted hearing this from other owners and stated they had no idea how to fix it; another dealership offered no solution
Recalls/TSBs owners mention: Temporary software update available (noted in complaint #14); no recall issued; voice recognition feature tied to active GPS per manufacturer response
Keyless entry / keyless-go system malfunction
Keyless-go system fails to lock/unlock vehicle or refuses entry. Panic alarm button inoperable. Doors lock on their own with occupants and valuables inside. System design allows rear door handle to unlock all doors when key is in possession.
When: Various; one incident on extremely hot day with dog inside
Symptoms owners cite: Keyless entry will not unlock vehicle; Panic alarm button non-functional; Doors lock themselves unexpectedly, trapping occupants; Design flaw: rear door handle unlocks all doors when key is nearby
Repairs/costs cited: Manufacturer does not know how or why failure occurs or how to fix; no backup for panic button if battery fails; one incident required police to break door open; dog was in vehicle on extremely hot day (over 100°F)
Recalls/TSBs owners mention: No solution provided; manufacturer acknowledged system design flaw (rear door unlock feature) as 'standard' and not a safety issue per owner letters to MBUSA and Daimler CEO
Stop/Start system malfunction
Automatic STOP/START system activates at stop light but vehicle cuts out completely on acceleration attempt, illuminating multiple unknown warning lights. Vehicle must be manually restarted.
When: At 158k miles
Symptoms owners cite: Stop/Start system activates at idle; Multiple warning lights illuminate simultaneously; Vehicle powers off completely when brake is released; Requires manual restart
Repairs/costs cited: Failure resolved by turning off Automatic STOP/START feature; no dealer diagnosis or repair performed
Electrical system corrosion / flooding damage
Vehicle flooded by rain due to missing manufacturer plug from day of purchase. Electrical system corroded and required replacement multiple times. Vehicle experiences complete electrical failure, won't crank, dies mid-drive, and requires towing.
When: From purchase date 7/11/15; problems started September 2015; electrical system changed out twice by October 2016
Symptoms owners cite: Vehicle dies and won't crank; Complete electrical system failure; Entire system goes out without warning; Vehicle stranded multiple times requiring towing; Electrical system corrosion found internally
Repairs/costs cited: Electrical system replaced twice; last repair (returned 10/26/16 after 2 weeks) did not resolve issue; owner reports car 'running like a truck' since last repair
Recalls/TSBs owners mention: Mercedes service department performed multiple repairs; MBUSA offered no replacement or lemon law buyback despite repeated failures and documented shop visits
Unintended reverse engagement / sudden vehicle movement
Vehicle engages reverse without deliberate input while parked in garage with engine running. Occurs when auxiliary device (air pump) plugged into cigarette lighter. Car moves backward, dragging motorcycle, crossing driveway and into neighbor's vehicle.
When: Incident occurred immediately after plug-in of air pump adapter
Symptoms owners cite: Vehicle shifts into reverse without driver input; Car moves at low idle speed; Cannot be stopped by owner's physical effort; Drag of motorcycle produces sparks
Engine compartment debris accumulation / air intake design flaw
Air vent system at top of hood allows rain, leaves, and debris to enter engine compartment from windshield area. Owner's letters to MBUSA and Daimler CEO received response that debris in engine area is 'normal' and customer's responsibility to remove. Debris risk includes overheating, fire, wiring damage.
When: Identified soon after purchase
Symptoms owners cite: Water and debris accumulate in engine compartment at windshield; Air from grill circulates to windshield, drawing in external debris
Recalls/TSBs owners mention: MBUSA subordinate staff rejected complaint and stated debris accumulation is 'normal' and customer's responsibility; Daimler CEO referral was redirected back to MBUSA
Panoramic sunroof malfunction / separation
Panoramic sunroof makes loud air noise, fails to open or close properly. In one case, piece of sunroof flew off while driving on bridge in rain, causing water leak into interior and motor failure. Another case has matching symptoms to recalled VINs but VIN excluded from recall.
When: Various; one incident on bridge while raining
Symptoms owners cite: Loud air noise from panoramic sunroof while driving; Sunroof opens or closes improperly; Sunroof panel separation / pieces fly off vehicle; Water leaks into interior; Sunroof motor fails after water exposure
Repairs/costs cited: One owner told entire sunroof assembly needs replacement; motorcycle/piece run over on bridge
Recalls/TSBs owners mention: NHTSA Recall #21V197 (Bonding of Panoramic Sunroof Panel - Wave 2) exists but some VINs are excluded despite identical failure symptoms; parts may be unavailable
Recall parts unavailability (17V114000 electrical system recall)
Multiple owners received recall notification for NHTSA Campaign 17V114000 (Electrical System, Engine and Engine Cooling) but parts required for repair were unavailable for extended periods (60+ days), with no estimated arrival date provided. Starting current limiter and related electrical components.
When: Recall notice received February 2016 and later; issue persisted through 2017
Symptoms owners cite: Vehicle overheating (reported in one case at 20k miles, December 2016)
Repairs/costs cited: Parts unavailable; manufacturer could not provide ETA; some dealers stated parts not available anywhere in USA
Recalls/TSBs owners mention: NHTSA Campaign 17V114000 issued but remedial parts unavailable for months; manufacturer did not communicate ETA to dealerships or owners
Engine code P052E / PCV crankcase vent valve failure
Engine light illuminates, vehicle becomes jolty and stalls. Diagnostic reveals faulty PCV (positive crankcase ventilation) vent valve. Owners report this is a common, recurring issue across 2015–2018 C300 models. Part costs $400+; labor-intensive 6-hour replacement job.
When: Various mileages; one complaint cites issue every 30–60k miles for multiple customers
Symptoms owners cite: Engine light illuminates; Vehicle jolts and hesitates; Engine stalls when stopped
Codes mentioned: P052E
Repairs/costs cited: Part cost $400+; labor estimate 6 hours due to intensive work; part replacement difficult for owner maintenance; one owner reported $2400 repair cost
Recalls/TSBs owners mention: Mercedes refuses to recognize as a common issue; no recall issued despite owner reports of widespread occurrence and manufacturer design updates claim
Start button / ignition switch malfunction
Start button requires multiple presses to engage ignition. Vehicle takes 10+ seconds to respond to accelerator input after starting. Creates dangerous delays at intersections.
When: Unknown timing
Symptoms owners cite: Start button must be pressed multiple times (up to 5 times); Ignition switch not engaging on first press; 10-second delay before acceleration response
Airbag system malfunction
SRS malfunction light for passenger seat airbag. Passenger airbag light activates when occupied. One owner suspects Takata airbag issue not yet flagged for their VIN.
When: Unknown timing
Symptoms owners cite: SRS malfunction indicator light illuminates; Passenger airbag light comes on when seat is occupied
Codes mentioned: SRS malfunction
Recalls/TSBs owners mention: One owner reported MBUSA stated no recall for airbag issue; suspected unreported Takata airbag defect
Multiple simultaneous electrical system shutdown
Vehicle loses all or most electrical functions: traction control, ESP, Pre-Safe, blind spot detection, and cruise control become inoperative simultaneously while driving. Vehicle slows and must be powered off and restarted to recover.
When: At 27k miles; multiple occurrences on busy roads and highways
Symptoms owners cite: Dashboard display: PRE SAFE FUNCTIONS LIMITED, INOPERATIVE TRACTION CONTROL; ESP SYSTEM OFF, BLIND SPOT NOT ACTIVATED; Cruise control and other systems inoperative simultaneously; Vehicle slows down uncontrollably; Requires shutdown and restart to recover; Occurred 3–4 times on busy roads
Repairs/costs cited: Vehicle sent to shop; no resolution reported by time of complaint
Door/trunk warning light delayed or absent
Warning light for open doors and trunk does not activate immediately upon shifting to gear. Passenger doors and trunk only trigger warning at approximately 5 mph; driver door triggers immediately.
When: Design behavior confirmed in testing by manufacturer
Symptoms owners cite: No immediate alert when passenger doors or trunk opened and vehicle put in gear; Warning activates only after reaching ~5 mph
Recalls/TSBs owners mention: Mercedes-Benz confirmed this is normal behavior; manufacturer recommends driver ensure all doors closed before driving
Battery drain / electrical system shutdown command
Dashboard displays 'STOP VEHICLE SHIFT TO PARK LEAVE ENGINE RUNNING' with battery icon. Vehicle electrical system shuts off and cycles on/off repeatedly.
When: Unknown timing
Symptoms owners cite: Dashboard message: 'STOP VEHICLE SHIFT TO PARK LEAVE ENGINE RUNNING' with battery symbol; Electrical system cycles on and off; System goes 'haywire'
Hands-free / voice command feature removal after software update
Voice recognition and hands-free phone features disabled following safety recall software update. Manufacturer states feature only operates if active GPS present, but vehicle was purchased with feature active.
When: After safety recall update
Symptoms owners cite: Voice recognition feature no longer functions; Hands-free features disabled
Recalls/TSBs owners mention: Manufacturer stated voice recognition only operates with active GPS system, reversing prior functionality
Rodent damage to wiring / collision prevention assist warning
Collision Prevention Assist Plus warning illuminates due to rodents chewing wiring harness. Vehicle unrepaired at time of complaint.
When: At 1,800 miles
Symptoms owners cite: Collision Prevention Assist Plus warning illuminates; Rodent gnaw marks on wiring harness
Repairs/costs cited: Wiring harness replacement needed; vehicle not repaired
Synthesized from 47 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 1 most recent
Had electrical trouble with your 2015 Mercedes-Benz C-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 C-Class?
It's a meaningful issue. 47 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 24 complaints that reported odometer mileage, most electrical failures cluster between 8,200 and 40,000 miles, with the median around 21,000. A quarter of owners report trouble before 8,200; a quarter make it past 40,000. 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/2015/Mercedes-Benz/C-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.