EVAP LEAK DTC P0442, P0455, P0456 INFORMATION This bulletin has been amended. See AMENDMENT HISTORY on the last page. Please discard previous versions of this bulletin.
full bulletin at NHTSA ↗2012 INFINITI QX56 engine problems
moderate Owners of the 2012 INFINITI QX56 have filed 21 NHTSA complaints about the engine, typically surfacing around 96,450 miles at roughly $3,100 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See engine across all vehicles →
Failure mileage
Complaints
21
Recalls
0
Avg fix
$3,100
| Model year | engine complaints |
|---|---|
| 2011 QX56 | 33 |
| 2012 QX56 (this page) | 21 |
| 2013 QX56 | 14 |
When does it fail?
Of the 21 engine complaints filed for the 2012 INFINITI QX56, 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
Engine accounts for 36% of every owner complaint on file for this vehicle — the dominant problem area across 6 categories tracked.
Among the 5 model years of INFINITI QX56 in our records for engine problems, this one ranks #2 by owner-complaint volume.
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.
DTC P0456 CAUSED BY EVAP LEAK AT VENT CONTROL VALVE O-RING This bulletin has been amended. See AMENDMENT HISTORY on the last page. Please discard previous versions of this bulletin.
full bulletin at NHTSA ↗INFINITI; DTC P0456 CAUSED BY EVAP LEAK AT VENT CONTROL VALVE O-RING This bulletin has been amended. See AMENDMENT HISTORY on the last page. Please discard previous versions of this bulletin.
full bulletin at NHTSA ↗2005-2015 INFINITI VEHICLES; ECM REPROGRAMMING SERVICE INFORMATION This bulletin is no longer active. Please discard previous versions of ITB15-024.
full bulletin at NHTSA ↗VK56 CONNECTING ROD CAP BOLT SERVICE INFORMATION SERVICE INFORMATION A change has been made to the connecting rod cap bolt service part. The new service part (B in Figure 1) is visually different, but is a direct replacement for the original equipment part. IMPORTANT: See page 2 for the procedure to inspect the cap bolt service part for excessive stretch. If replacement of a single connecting rod cap bolt is indicated for any given connecting rod, both connecting rod cap bolts of the affected connecting rod must be replaced as a set.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
The 2012 Infiniti QX56 engine develops serious problems with the timing chain on the auxiliary (fuel pump) side. Owners consistently report the chain stretching, rubbing metal-to-metal, and eventually snapping. The failure usually shows up between 70,000 and 90,000 miles with a loud metallic rattle or grinding—especially at cold start—followed by loss of power, violent shaking, or stalling without warning. Engine light comes on, sometimes with codes P0011, P0021, or P0300.
Replacing the timing chain costs $4,000–$5,000 out of pocket for most owners; one dealer chain reportedly does 30–40 of these repairs per month. If owners ignore the noise and let it go, the engine tears itself apart and requires a full replacement at around $17,000. Infiniti knows about this defect—the 2013 model got a heavier-duty chain—and issued recall P6305, but many VINs got excluded. The company refuses to cover repairs outside warranty, calling it normal wear even though owners report proper maintenance from day one.
Catalytic converters also fail early, typically after 113,000 miles or sooner if they were previously replaced under the recall. Owners cite repeated replacement needs and costs above $4,500. One owner replaced the converter under recall, then again just 35,000 miles later.
Same INFINITI QX56 engine reports on nearby years: 2011 · 2013
Failure modes owners describe
Timing chain stretch and failure
The timing chain on the auxiliary (fuel pump) side stretches, rubs metal-to-metal, and eventually breaks or fails catastrophically. Owners report this as a widespread defect on 2010–2012 QX56 models; Infiniti introduced a heavier-duty replacement chain for 2013. The failure can trigger complete engine damage if not repaired.
When: 60,000 to 175,000 miles; most commonly reported between 70,000–90,000 miles
Symptoms owners cite: Loud rattling or grinding noise from timing chain area, worse at cold start (described as 'screaming eagle'); Whining noise at startup and during acceleration; Engine shaking or violent shaking while driving; Loss of power and failure to accelerate; Engine stall without warning; Check engine light illumination (codes P0011, P0021, P0300 cited); Sputter and rough idle
Codes mentioned: P0011, P0021, P0300
Repairs/costs cited: $4,000–$5,000 to replace timing chain and related components; full engine replacement estimated at $17,000 if damage is severe. One owner paid $4,000 out of pocket at 83,000 miles, just 10,000 miles beyond warranty expiration. Dealers report performing 30–40 of these repairs per month.
Recalls/TSBs owners mention: Infiniti acknowledges the defect is known and fixed on 2013 models with heavier-duty chain. Partial recall (P6305) issued but many VINs excluded. Infiniti refuses coverage out of warranty, stating it is not a common problem despite overwhelming owner evidence.
Catalytic converter failure
Both driver and passenger catalytic converters fail prematurely. Owners report repeated replacement—some within 35,000 miles of the first recall repair. Failures occur on vehicles that were properly maintained from new and had converters replaced under recall.
When: 113,000 to 134,000 miles on original units; 35,000 miles after recall replacement
Symptoms owners cite: Check engine light illumination (P0430 code: Catalyst System Efficiency Below Threshold); Engine stalling
Codes mentioned: P0430
Repairs/costs cited: $4,500–$5,200 to replace both catalytic converters. One owner required replacement twice in one year under warranty, then again at 134,000 miles.
Recalls/TSBs owners mention: Infiniti issued a recall for catalytic converters (mentioned in narrative #17), but owners report failures recurring shortly after recall work. Warranty is 80,000 miles.
High-pressure fuel pump failure and secondary timing chain damage
Fuel pump leaks and fails, which cascades into timing chain failure. One owner reported the fuel pump leak caused the timing chain to fail; another found fuel pump failure triggered timing chain breakdown and engine damage.
When: 70,000 miles; mileage unknown for one case
Symptoms owners cite: Loss of motive power at highway speed; Vehicle slows down and fails to respond to throttle; Stalling
Codes mentioned: P0021, P0011, P0300
Repairs/costs cited: One owner was told fuel pump alone needed replacement; independent mechanic later diagnosed timing chain failure and engine replacement necessity. Another owner cited $4,000–$5,000 repair cost for the chain aspect.
Recalls/TSBs owners mention: Infiniti customer service indicated vehicle was ineligible for recall campaign P6305.
Power steering pump failure (possibly secondary to timing chain issue)
Power steering pump failure reported at approximately 70,000 miles. Independent mechanic replaced it, but the humming noise recurred; Infiniti dealer then attributed the humming to timing chain wear.
When: 70,000 miles
Symptoms owners cite: Humming noise from engine; Loss of power and failure to accelerate
Repairs/costs cited: Power steering pump was replaced by independent mechanic; noise returned, leading to timing chain diagnosis.
Synthesized from 21 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 6 most recent
Vehicle dropped speed on the highway and started flashing the service engine soon light. The speed drop was severe and placed me in a dangerous situation on the highway. It also had a whining noise at start when I left . Took it to the dealer, they informed me the timing chain needed to be replaced. The vehicle only had 83k in miles and was just 10k out of warranty. Dealer charged $4000 for…
Tl* the contact owns a 2012 Infiniti qx56. The contact stated that the vehicle lost power and failed to accelerate. In addition, there was a humming noise coming from the engine. There were no warning indicators illuminated. The vehicle was taken to west houston Infiniti (12200 katy fwy, houston, tx 77079, (281) 589-8900) where it was diagnosed that the brakes were wearing down. The contact…
At 82,000 miles the check engine light came on indicating both catalytic converters were bad. They are warrantied to 80k miles and of course manufacturer would not help. This needs a recall, google qx56 catalytic converter and see how many people have had this issue.
I own a 2012 QX56. Check engine light comes on and I take it to the dealer. It's the Catalyst System Efficiency Below Threshold (catalytic covers - P0430 code) I was warned before I bought this vehicle about the cats going bad. Infiniti dealer, that I purchased the truck from said "this vehicle has been serviced at an Infiniti dealer since day one. Every possible service that was needed was…
I had my catalytic converter replaced back in december 2016 . There was a recall for catalytic converter so I had it replaced. Now the check engine light is back on so I got it checked out and was told that I needed to replace the catalytic converter again. 35k miles later
I am experiencing the same issues that have been posted by several others on this site with the catalytic converter and the battery (jn8az2ne3c9****, jn8az2nf1c9****, and jn8az2nc9c9****). I took it to get checked out yesterday and just received a call from the technician. He stated that both catalytic converters have to be replaced and it will cost $5,200. If this is a common issue, why is…
Had engine trouble with your 2012 INFINITI QX56?
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 2012 INFINITI QX56?
It's a documented issue but not catastrophic. 21 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Across the 15 complaints that reported odometer mileage, most engine failures cluster between 82,000 and 130,000 miles, with the median around 96,450. A quarter of owners report trouble before 82,000; a quarter make it past 130,000. 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 $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/2012/INFINITI/QX56.
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.