Check engine light illuminated - Fault code current P04D-B79 The crankcase ventilation system is interrupted. Complaint: Check engine light on. Fault code P04DB79 is current in the engine control module (N3/10). Cause: Open circuit or high resistance to crankcase vent line contact Remedy 1. Check the electrical connector for S208 vent line contact switch. Refer to attached photo of connection location. 2. Ensure the bolted connection is secure and bolt can be torqued (9Nm). 3. Check continuity from vent line connection to ME control unit. Repair wire if damage is found.
full bulletin at NHTSA ↗2016 Mercedes-Benz Metris engine problems
severe 13 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Complaints
13
Recalls
0
Avg fix
$3,100
1fire
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
M274 poly-V belt squeaking noises, falls off, not aligned, broken
full bulletin at NHTSA ↗SMOG/Emissions Test fail due to one or more Readiness Monitors not set Complaint: The vehicle has failed the State Emissions Certification because one or more of the OBDII readiness monitors are not completely set. Cause: One or more of the following Readiness Monitors are not fully set within XENTRY: Misfire Monitoring - Injection System Fuel System Monitoring - Injection System, Fuel System, EGR Valve, O2 Sensor NMHC Catalyst Monitoring - NMHC/Diesel Oxidation Catalyst NOx Aftertreatment Monitoring - SCR Catalyst System Boost Pressure System Monitoring - Turbocharger, Charge Air System Exhaust Gas Sensor Monitoring - O2 Sensor, NOx Sensors Diesel Particulate Filter Monitoring - Diesel Part
full bulletin at NHTSA ↗Stop Sale for Pending Emission Modification
full bulletin at NHTSA ↗Initial Notice - STOP SALE - Pending Emissions Modification
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Check engine light and code P052E dominate the complaints: owners report crankcase ventilation valve and PCV assembly failures kicking in around 50,000–60,000 miles. Multiple owners cite this as a known defect identical to what Mercedes passenger models with the M274 engine have—except the passenger vehicles get extended warranty coverage while the commercial Metris is excluded. Repair costs run to $3,000 or more.
Rough idle, difficult starting, and oil leaks accompany the code P052E failures. One owner documented recurrence 98,000 miles after the first repair. Timing chain damage also appears in the cluster, showing check engine light, rough driving, and hard starts at 32,000 miles and recurring at higher mileage; dealers recommended full engine replacement in some cases. A separate failure involved intake camshaft position sensor malfunction with the camshaft 180 degrees out of sync, causing power loss underway. Fuel hose leakage from the tank to high-pressure pump caused engine knock and shaking. One report notes gasoline odor inside the cabin during cold weather.
Across complaints, the core grievance is warranty exclusion: the Metris uses the same engine as covered passenger models yet sits outside the extended warranty umbrella.
Failure modes owners describe
Crankcase ventilation valve (PCV) failure
Crankcase ventilation/vent assembly and PCV valve defect causing check engine light illumination and code P052E. Owners report this is a known defect on Mercedes passenger models with the same M274 engine, covered under extended warranty on those vehicles but not on the Metris commercial variant. Multiple owners cite $3,000+ repair costs.
When: Typically 50,000–60,000 miles; one report at 52,000 miles
Symptoms owners cite: Check engine light illuminated; Code P052E or P052E71; Rough driving; Difficult to start; Oil leakage; Prevents state vehicle inspection passage
Codes mentioned: P052E, P052E71
Repairs/costs cited: Replacement of crankcase ventilation valve; owners report repair costs up to $3,000. One owner noted dealer confirmed multiple oil leaks and other service required at extensive cost.
Recalls/TSBs owners mention: Extended warranty available on passenger models with M274 engine; commercial Metris excluded from coverage despite having identical engine and defect
Timing chain damage
Engine timing chain failure causing check engine light, rough operation, and difficult starting. One report documented recurrence at 98,000 miles after initial repair. Dealers recommended engine replacement in some cases. Multiple vehicles in the same fleet affected with identical failures.
When: First occurrence at 32,000 miles; recurrence at 98,000 miles after repair. Another report at 60,000 miles; another at 171,000 miles
Symptoms owners cite: Check engine light illuminated; Rough driving; Difficult to start
Codes mentioned: P052E
Repairs/costs cited: One case: engine timing chain repaired; failure recurred 98,000 miles later. Other cases: engine replacement recommended but not completed. Multiple vehicles in same fleet had identical failure.
Intake camshaft position sensor malfunction
Intake camshaft position sensor failure with camshaft out of sync by 180 degrees, causing loss of power and engine functionality during operation.
When: Mileage not stated
Symptoms owners cite: Loss of power; Loss of engine functionality while underway; Camshaft out of sync by 180 degrees
Codes mentioned: Position of intake camshaft implausible
Fuel hose leakage
Lower fuel hose from tank to high-pressure pump leaking, causing engine knocking sounds and loss of power.
When: Mileage not stated
Symptoms owners cite: Engine knocking and noises; Vehicle shaking intermittently; Lack of power after knocking; Gasoline smell; Fuel leaks
Repairs/costs cited: Fuel hose and clamps replaced
Fuel odor in cabin (cold weather)
Interior gasoline smell occurring more frequently in cold outside temperatures.
When: Multiple occurrences in cold weather
Symptoms owners cite: Gasoline smell inside vehicle; Occurs in cold outside temperatures
Synthesized from 13 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 0 most recent
Had engine trouble with your 2016 Mercedes-Benz Metris?
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 engine problem on the 2016 Mercedes-Benz Metris?
It's a meaningful issue. 13 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $3,100.
At what mileage does the engine typically fail?
Based on the 13 complaints filed, engine issues most often appear around 64,200 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 $3,100 for engine 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 engine?
No active recalls currently cover engine 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/2016/Mercedes-Benz/Metris.
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.