The 2015 CX-9 with the 3.7L V6 is a solid three-row crossover, but it's plagued by a critical transmission oil cooler failure that can destroy the transmission, and some units experienced catastrophic engine failure due to piston ring land issues—both expensive problems that define ownership risk at higher mileage.
Transmission Oil Cooler Failure Leading to Transmission Contamination
Common · high severity
Typical onset: 80,000-130,000 mi
Symptoms: Pink or strawberry milkshake-colored transmission fluid (coolant mixing with ATF), Transmission slipping, delayed engagement, or complete failure, Overheating transmission or engine, Check engine light with transmission codes
Fix: The internal transmission oil cooler (inside the radiator) fails and allows coolant to mix with ATF, contaminating the transmission. If caught early, flush transmission and replace radiator (4-6 hours). If driven after contamination, requires transmission rebuild or replacement (12-18 hours total). This is a known design flaw across this generation.
Estimated cost: $800-1,200 (cooler only) or $3,500-5,500 (with transmission rebuild/replacement)
Piston Ring Land Failure and Catastrophic Engine Damage
Occasional · high severity
Typical onset: 60,000-120,000 mi
Symptoms: Excessive oil consumption (quart every 500-1,000 miles), Blue smoke from exhaust on startup or acceleration, Loss of compression, misfires, Catastrophic failure: knocking, metal shavings in oil, seized engine
Fix: Some 3.7L engines experience piston ring land fractures, leading to blow-by and eventually total engine failure. Minor cases need all pistons and rings (25-30 hours), severe cases require short block or complete engine replacement (30-40 hours). This is a design weakness in certain production batches.
Estimated cost: $4,500-7,000 (piston/ring job) or $6,000-9,000 (short block/engine replacement)
Transmission Mounts Collapsing
Common · medium severity
Typical onset: 70,000-110,000 mi
Symptoms: Clunking when shifting from Park to Drive/Reverse, Vibration through chassis during acceleration, Excessive engine movement visible under hood during gear changes
Fix: The rear transmission mount deteriorates and collapses, especially on vehicles with towing history. Replacement is straightforward but requires supporting the transmission. Replace both engine and transmission mounts as a set (2.5-3.5 hours).
Estimated cost: $400-650
Power Liftgate Struts and Motor Failure
Common · low severity
Typical onset: 60,000-100,000 mi
Symptoms: Liftgate opens partially then stops or falls, Grinding or clicking noise from liftgate actuator, Intermittent liftgate operation or complete failure to open/close
Fix: Power liftgate struts wear out and lose pressure, causing slow or incomplete operation. Motor and control module can also fail. Struts are easy (1 hour), motor replacement requires trim removal and recalibration (2-3 hours).
Estimated cost: $300-500 (struts) or $800-1,200 (motor/module)
Fuel Filter Clogging (In-Tank)
Occasional · medium severity
Typical onset: 90,000-140,000 mi
Symptoms: Hesitation or stumbling during acceleration, Difficulty starting after sitting, Loss of power at highway speeds, Check engine light with fuel pressure/lean codes
Fix: The in-tank fuel filter (part of the pump assembly) clogs from contaminated fuel or sediment buildup. Requires dropping the fuel tank and replacing the entire pump assembly (3-4 hours). Not a maintenance item in Mazda's schedule, but should be addressed when symptoms appear.
Estimated cost: $600-900
Front Lower Control Arm Bushings Separating
Common · medium severity
Typical onset: 75,000-120,000 mi
Symptoms: Clunking over bumps from front suspension, Wandering or imprecise steering, Uneven tire wear on inside edges, Visible separation between bushing and control arm
Fix: The front lower control arm rear bushings deteriorate and separate, especially in rust belt climates. Mazda doesn't sell bushings separately—requires complete control arm replacement on both sides (2.5-3 hours per side, alignment required).
Estimated cost: $800-1,200 (both sides with alignment)
Owner tips
Check transmission fluid color religiously—pink or milky fluid means immediate oil cooler replacement before the trans is destroyed
Monitor oil consumption closely; if burning more than a quart every 2,000 miles, have compression tested before catastrophic failure
Replace transmission oil cooler proactively around 80,000 miles with an external unit to prevent the mixing issue entirely
Use Top Tier fuel to minimize fuel filter contamination—this platform is sensitive to fuel quality
A capable and comfortable family hauler IF the transmission oil cooler has been addressed and the engine isn't consuming oil—otherwise, you're gambling on two potential four-figure repairs that are common enough to be deal-breakers above 100k miles.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
Fitment notes: Standard battery location under hood; some models may use Group 24F
As an Amazon Associate, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Every control module on the 2008-2015 Mazda CX-9 — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
📍 Rear cargo area, driver side trim panel behind wheel well
🔧 Autel or Launch
⚠️ Sensor calibration may be required after replacement
Rear View Camera Module (RVM)0.5 hr R&Rrelearn only +0.1 hrwith rear view camera▸ programming details
📍 Integrated with rear liftgate camera assembly
🔧 Self-relearn on ignition cycle
⚠️ Camera calibration lines may require adjustment via audio unit settings
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
AIR BAGS:FRONTAL:PASSENGER SIDE:INFLATOR MODULE · 18V717000
2018-10-12 · EA15001
Mazda North American Operations (Mazda) is recalling certain 2014-2015 Mazda CX-9 vehicles sold, or ever registered in the states of Alabama, California, Florida, Georgia, Hawaii, Louisiana, Mississippi, South Carolina, Texas, Puerto Rico, American Samoa, Guam, the Northern Mariana Islands (Saipan), and the U.S. Virgin Islands or "Zone A."
Additionally, unless covered in "Zone A," Mazda is recalling certain 2011-2013 Mazda6, 2011-2012 CX-7, and 2011-2015 CX-9 sold, or ever registered in the states of Arizona, Arkansas, Delaware, Illinois, Indiana, Kansas, Kentucky, Maryland, Missouri, Nebraska, Nevada, New Jersey, New Mexico, North Carolina, Ohio, Oklahoma, Pennsylvania, Tennessee, Virginia, West Virginia and the District of Columbia, or "Zone B."
Additionally, unless covered in Zone A or Zone B, Mazda is recalling certain 2010-2013 Mazda6, 2010-2012 CX-7, and 2010-2015 CX-9 vehicles ever registered in the states of Alaska, Colorado, Connecticut, Idaho, Iowa, Maine, Massachusetts, Michigan, Minnesota, Montana, New Hampshire, New York, North Dakota, Oregon, Rhode Island, South Dakota, Utah, Vermont, Washington, Wisconsin, and Wyoming or "Zone C."
These vehicles are equipped with certain air bag inflators assembled as part of the passenger frontal air bag modules used as original equipment or replacement equipment. In the event of a crash necessitating deployment of the passenger frontal air bag, these inflators may explode due to propellant degradation occurring after long-term exposure to absolute humidity and temperature cycling.
Consequence: An inflator explosion may result in sharp metal fragments striking the driver or other occupants resulting in serious injury or death.
Remedy: Mazda will notify owners, and dealers will replace the front passenger air bag inflator with an alternate inflator, free of charge. The recall began November 9, 2018. Owners may contact Mazda customer service at 1-800-222-5500, Option 4. Mazda's number for this recall is 1317F.
STEERING · 16V203000
2016-04-11
Mazda North American Operations (Mazda) is recalling certain model year 2016 CX-3 vehicles manufactured June 1, 2015, to December 2, 2015, 2013-2014 Mazda2 vehicles manufactured July 3, 2013, to August 8, 2014, 2014-2016 CX-5 vehicles manufactured January 19, 2013, to December 2, 2015, and 2013-2015 CX-9 vehicles manufactured December 6, 2012, to July 31, 2015. The lower mounting nuts and bolts that attach the front strut assembly to the steering knuckle may loosen, allowing the steering knuckle to separate.
Consequence: If the steering knuckle separates from the strut assembly, it can cause a loss of steering control, increasing the risk of a crash.
Remedy: Mazda will notify owners, and dealers will inspect the lower mounting nuts and bolts that secure the front strut assembly to the steering knuckle. If the bolts are loose, they will be replaced and then correctly tightened, free of charge. The recall is expected to begin May 20, 2016. Owners may contact Mazda customer service at 1-800-222-5500. Mazda's number for this recall is 9316D.
Fuel economy (EPA)
City
17mpg
Highway
24mpg
Combined
19mpg
Fuel
Regular Gasoline
Capability & size
EPA class
Small Sport Utility Vehicle 2WD
Wiper blades
First generation (TB) 2007-2015. Standard hook-type attachment for all blades.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2015 Mazda CX-9 3.5L V6 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.