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 ↗2011 INFINITI QX56 engine problems
moderate Owners of the 2011 INFINITI QX56 have filed 33 NHTSA complaints about the engine, typically surfacing around 102,074 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
33
Recalls
0
Avg fix
$3,100
| Model year | engine complaints |
|---|---|
| 2011 QX56 (this page) | 33 |
| 2012 QX56 | 21 |
| 2013 QX56 | 14 |
When does it fail?
Of the 33 engine complaints filed for the 2011 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
Of the 5 model years of INFINITI QX56 we track for engine problems, this one carries the most owner complaints on file — 33.
Engine accounts for 43% of every owner complaint on file for this vehicle — the dominant problem area across 4 categories tracked.
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.
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full bulletin at NHTSA ↗2005-2015 INFINITI VEHICLES; ECM REPROGRAMMING SERVICE INFORMATION This bulletin is no longer active.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 ↗These SKUs are Exhaust Manifolds with Catalytic Converters. The customer communication requested return of unsold inventory due to a loss of CARB certification. These SKUs can no longer be sold as they do not meet CARB standards, but parts on vehicles are not effected.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Timing chain noise and failure dominates the 2011 QX56 owner complaints. The problem manifests as a whining or whistling noise on cold start, progressing to loud rattling and squealing, especially under acceleration. Owners consistently report that Infiniti dealers immediately identify the symptom—so familiar that multiple technicians recognize it before the engine is even started. The issue stems from a defective oil pump that fails to properly lubricate the chain. Some vehicles fail twice: once repaired at 73,000 miles, then again at 169,000 miles. Timing chain replacement costs exceed $4,500, with one dealer maintaining a dedicated technician just for this failure. The manufacturer issued Service Bulletin TSB 16-015 and Voluntary Service Campaign P6305 in 2016, but many VINs remain excluded from recall coverage.
Catalytic converter failures are equally prevalent and often occur in pairs. Bank 1 and Bank 2 converters have failed within days of each other. Owners report failures beginning at 72,000 miles; some experience dual converter failure requiring $5,600 in repairs to pass emissions testing. One owner's Bank 2 converter failed March 29, 2018; Bank 1 failed March 31. Infiniti Consumer Affairs acknowledged the issue in partial settlements but declined to cover already-paid repairs. Dealers confirm the problem is well-known, yet no official recall exists.
Fuel system codes (P0087) and VVT solenoid issues also appear linked to voluntary recalls, but many VINs fail to register in the recall database despite owners locating the campaigns.
Same INFINITI QX56 engine reports on nearby years: 2012 · 2013
Failure modes owners describe
Timing Chain Noise and Failure
Timing chain develops noise on cold start or during operation, progressing to complete failure requiring replacement. Owners report the defect stems from a faulty oil pump that insufficiently lubricates the chain. The issue is confirmed by dealers immediately upon hearing the symptom, indicating it's a known, recurring problem. Some vehicles experience timing chain failure twice—once repaired, it fails again at higher mileage.
When: Typically 72,000 to 200,500 miles; cold start complaints begin earlier, around 78,000–120,000 miles
Symptoms owners cite: Whining noise during cold start-up; Loud whistle noise from engine during start; Squealing and clapping noise when accelerating; Rattling noise from engine compartment after starting; Jerking and abnormal engine noise during acceleration at highway speeds; Loss of motive power on incline; Engine vibration; Intermittent power loss and limp mode
Codes mentioned: Timing chain failure (no specific OBD code cited, but diagnosed visually/by symptom)
Repairs/costs cited: Timing chain replacement cost exceeds $4,500 at dealership. One owner reported the defect prompted re-engineering of replacement parts. Vehicle repaired once at 73,000 miles required second timing chain replacement at 169,000 miles. One independent shop visit found no code initially, then codes for timing chain appeared after reset.
Recalls/TSBs owners mention: Service Bulletin TSB 16-015 and Voluntary Service Campaign P6305 issued (2016). Some owners excluded from recall due to VIN not appearing in recall database. One owner reported campaign expired in February 2018, leaving them without coverage. Another informed vehicle was not included in an unknown manufacturer recall for engine timing chain.
Catalytic Converter Premature Failure
Bank 1 and Bank 2 catalytic converters fail prematurely, often in pairs or serially. Multiple failures within days or months of initial repair occur. One owner's Bank 2 converter failed on March 29, 2018; Bank 1 failed two days later on March 31. Another reports left-side replaced in 2013, right-side in 2016, left-side failing again. Dealers indicate this is a known issue, yet it remains unfixed.
When: As early as 72,000–83,000 miles; recurring failures within months of repair
Symptoms owners cite: Check engine light illumination; Catalytic converter dysfunction requiring replacement
Codes mentioned: P0420 – Catalyst System Inefficiency, P0430 – Catalyst System Inefficiency
Repairs/costs cited: Bank 2 replacement: $2,661.79 (parts and labor). Bank 1 replacement: $1,385.63 labor; parts covered by Infiniti Consumer Affairs. Another owner quoted $2,000 for single converter. A dealer quoted $5,600 to replace both converters; another cited $3,100 for converter and A/F sensor repair. Multiple owners report dual converter replacement required to pass smog testing.
Recalls/TSBs owners mention: Infiniti Consumer Affairs provided partial assistance in one case, covering parts for second failure but not first. They acknowledged the issue as known to warrant a gesture. No formal recall issued. One owner post-timing-chain repair experienced check engine light due to catalytic converter 8 months later.
Fuel System Issues and Related Codes
Owners report diagnostic codes and service campaigns related to fuel system components, including high-pressure fuel pump, fuel injector issues, and VVT solenoid failures. One owner received code P0087 and was directed to dealership because the issues fall under a voluntary safety recall campaign, yet the vehicle VIN did not appear in recall records.
When: Unspecified mileage in available narratives
Symptoms owners cite: Check engine light; Code P0087 (fuel system pressure too low)
Codes mentioned: P0087
Repairs/costs cited: No specific repair costs or parts cited in narratives for fuel system failures.
Recalls/TSBs owners mention: Voluntary safety recall campaigns mentioned for fuel system, timing chain, VVT solenoids, and high-pressure fuel pump, but VINs not appearing in recall database despite owners researching and locating these campaigns.
Synthesized from 33 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 8 most recent
Engine is making a loud noise on the front right side. Took it to my mechanic and he said is the timing chain and oil jet.
Tl* the contact owns a 2011 Infiniti qx56. The contact heard an abnormal noise coming from the vehicle. The vehicle was taken to pearson Infiniti (11701 midlothian turnpike, midlothian, va 23113, 1-(804) 527-0300) where it was diagnosed that the timing chain needed to be replaced. The contact was informed that the dealer would check tsb number: 16-015 and voluntary service campaign: p6305 to…
Tl* the contact owns a 2011 Infiniti qx56. When the vehicle was started, an unusual noise was heard from the engine and the check engine indicator illuminated. The vehicle was taken to nalley Infiniti marietta (404-994-4328, located at 2020 cobb pkwy se, marietta, ga 30060) where it was diagnosed that the timing belt needed to be replaced. The manufacturer was not made aware of the failure. The…
Tl* the contact owns a 2011 Infiniti qx56. While operating the vehicle, a rattling noise was present coming from the engine compartment. The rattling noise became more prevalent after starting the engine. The vehicle was examined by an independent mechanic who indicated that the timing belt was faulty. The vehicle was not repaired. The manufacturer was notified, but no assistance was offered. The…
Tl* the contact owns a 2011 Infiniti qx56. While driving 60 to 65 MPH, the vehicle jerked and an abnormal noise was heard from the engine area. Also, the service engine indicator illuminated. The contact had to decelerate due to the noise. The contact drove the vehicle to an independent mechanic to be diagnosed, but no failure code was found initially. The mechanic reset the codes, test drove the…
Tl* the contact owns a 2011 Infiniti qx56. The contact heard an abnormal noise when the vehicle was being fueled and the check engine warning indicator illuminated. The vehicle was not taken to a dealer or an independent mechanic for diagnostic testing. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 126,557.
Tl* the contact owns a 2011 Infiniti qx56. While driving various speeds, the check engine warning indicator illuminated continuously. The vehicle was taken to sewell Infiniti of fort worth (5135 bryant irvin rd, fort worth, tx 76132) where it was diagnosed that the catalytic converter needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The…
"takata recall" only owner of 2011 qx56, always on time with proper maintance. After a recall on the timing chain 2 days after picking up vehicle the service engine light came on, I called the dealer they advised it was normal to give it a few days. After 3 days light ses light came off, then about 8 months later the service engine soon light was back, got it checked and it's the catalytic…
Had engine trouble with your 2011 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 2011 INFINITI QX56?
It's a documented issue but not catastrophic. 33 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 24 complaints that reported odometer mileage, most engine failures cluster between 89,000 and 126,557 miles, with the median around 102,074. A quarter of owners report trouble before 89,000; a quarter make it past 126,557. 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/2011/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.