AI Damage2018 Mazda CX-9: common problems
Owners of the 2018 Mazda CX-9 filed 128 complaints with NHTSA, most often about engine and electrical system. The maker issued 289 service bulletins for this year. Details by component below, with sources.
Key figures
- Owner complaints
- 128
- involving a crash
- 4
- Technical service bulletins (TSB)
- 289
What fails most often
- 1 Engine 59% of all complaints
- 2 Electrical system 12% of all complaints
- 3 Powertrain 10% of all complaints
- 4 Service brakes 9% of all complaints
- 5 Fuel/propulsion system 4% of all complaints
- 6 Forward collision avoidance 3% of all complaints
- 7 Steering 2% of all complaints
- 8 Visibility 2% of all complaints
- Engine: 76 complaints (59% of all); manufacturer bulletins for this component: 24.
- Electrical system: 15 complaints (12% of all); manufacturer bulletins for this component: 84.
- Powertrain: 13 complaints (10% of all); manufacturer bulletins for this component: 29.
- Service brakes: 11 complaints (9% of all), 2 of them with a crash reported by the owner; manufacturer bulletins for this component: 23.
- Fuel/propulsion system: 5 complaints (4% of all); manufacturer bulletins for this component: 6.
Engines and transmissions
US-market versions per EPA. On the right: how many NHTSA complaints name this engine or transmission type.
- 2.5 L · petrol · turbo · 4 cyl
- automatic, 6-speed
Drive: FWD, 4WD
Symptoms owners describe
How many of the 128 NHTSA complaints mention each symptom (automatic count from complaint text; one complaint can mention several).
Components owners complain about
| Component | Owner complaints | involving a crash | Technical service bulletins (TSB) |
|---|---|---|---|
| Engine | 76 | 0 | 24 |
| Electrical system | 15 | 0 | 84 |
| Powertrain | 13 | 0 | 29 |
| Service brakes | 11 | 2 | 23 |
| Fuel/propulsion system | 5 | 0 | 6 |
| Forward collision avoidance | 4 | 0 | 6 |
| Steering | 3 | 0 | 15 |
| Visibility | 3 | 1 | 9 |
| Backover prevention | 3 | 0 | 1 |
| Engine and cooling | 2 | 0 | 39 |
| Fuel system | 2 | 0 | 2 |
| Seats | 2 | 0 | 2 |
| Air bags | 2 | 2 | 1 |
| Structure | 1 | 0 | 23 |
What owners report
Short excerpts of NHTSA complaints in the original wording. These are owner statements not verified by NHTSA; personal data removed.
Emergency parking brake ('epb') began to malfunction following recall to fix electrical components on mazda cx-9, 2018. Epb will not release, or will unexpectedly and suddenly release with car accelerating in gear ('drive' or 'reverse').
My air bags didn't deploy when I was I a accident . I've taken it to the dealer 3 times already and they always have a different excuse or reason
Takata recall - was in a head on collision with 3 other cars involved, all cars were totaled and all of the other cars' airbags deployed with the exception of mine and I was injured as a result.
While driving at highway speed in heavy rain the oil light suddenly came on followed within 30 seconds by an urgent need to immediately stop the car due to overheating. There was no radiator fluid left due to the sudden and catastrophic structural failure caused by a known manufacturing defect. Mazda calls it csp-11.
The vehicle began to lose coolant with no apparent external leak and subsequently displayed and engine -overheating warning. It continued to lose coolant after a flush.
I was driving home from work and may car started overheating out of nowhere. I was stuck in traffic and white smoke was exiting my exhaust. I pulled over and all of my coolant leaked out of my car. Took it the shop and they said I had a cracked head and need a whole new engine.
Then while I'm driving on the highway my seat started to smoke a lot I got scared and pulled on side of the road. I realized my seat was the issue turned off the heated seats on the control. Step out the vehicle on side the highway I was nervous and scared standing outside my vehicle.
This is a known design defect documented in Mazda TSB 01-002/23 and addressed by Customer Service Program CSP11, which extended the powertrain warranty to 10 years/120,000 miles for coolant leaks at the cylinder head.
When owners complained
NHTSA complaints by filing year. The peak shows at what age the problems show up most.
Comparison
By complaint count this model year ranks 483 of 2,102 model years in the NHTSA data (top 23% most complained about).
On average one model year of the CX-9 has 53 complaints (8 years in the data). This year has 128, above average.
What to check before buying
- Engine. Cold start, unusual noises, oil leaks and engine codes.
- Electrical system. Scan all modules, test the battery and alternator, inspect connectors near the impact zone.
- Powertrain. Shift quality under load, harsh shifts, transmission codes, CV joints.
- Service brakes. Pedal feel, ABS operation, leaks, discs and hoses.
Manufacturer service bulletins
Bulletin titles as filed with NHTSA.
- If you encounter any type of electrical concern (e.g, dead battery, engine no start, DTC(s) stored...),…
If you encounter any type of electrical concern (e.g, dead battery, engine no start, DTC(s) stored...), interview the customer before proceeding with normal MGSS diagnosis by asking if any aftermarket devices have been…
- Some vehicles may require the replacement of a damaged VIN plate or vehicle certification label
To obtain a replacement VIN plate (bulkhead-mounted and visible through the lower-left area of the windshield), contact DAG (Dealer Assistance Group) using VIN Plate Request Form available on One Mazda. To obtain a…
- Mazda has developed factory recommended scheduled maintenance services that support all major vehicle systems
Mazda recommends dealers follow the scheduled maintenance tables as cited in the vehicle-specific workshop manual or owner's manual. Services performed outside of Mazda's factory scheduled maintenance are not…
- If an engine assembly is replaced after a catastrophic internal mechanical failure, clean the intake…
If an engine assembly is replaced after a catastrophic internal mechanical failure, clean the intake manifold internally before installing a replacement engine assembly. If the intake manifold is not cleaned properly…
- Some vehicles may exhibit rattling noises from the engine compartment and oil leakage from the drive belt…
Some vehicles may exhibit rattling noises from the engine compartment and oil leakage from the drive belt auto tensioner. This may be caused by insufficient sealing at the drive belt auto tensioner damper when the auto…
- There is a concern that some water pumps are being replaced that are not faulty, due to signs of a very…
There is a concern that some water pumps are being replaced that are not faulty, due to signs of a very small coolant leak from the bleed hole. This Service Alert is to inform you about the water pump sealing mechanism…
- There are currently 2 methods for cutting a new auxiliary key blank
A. Auxiliary Key Trace Cut Method • B. Auxiliary Key Code Cut Method 2019 and newer models require a 10-digit key code to accurately cut keys • 5-digit codes CANNOT be provided for 2019 and newer vehicles (the…
- Some customers may report an odor or water in the HVAC system and upon inspection, the cabin air filter…
Some customers may report an odor or water in the HVAC system and upon inspection, the cabin air filter may be found to be wet.
- A musty/mildew type odor may come from the vents when the air conditioning (A/C) system is operating
It is most noticeable when the A/C is first turned ON. This odor is the result of mold growth in the A/C evaporator/cooling unit which is caused by condensation, dust, and pollen within the cooling unit. This condition…
- When inspected, the differential or PTO oil is dark or black
This is considered normal and NO repair should be performed. During production, differential ring and pinion gears receive a manganese phosphate coating (commonly referred to as black oxide). This coating forms a…
- Some vehicles exhibit brake related concerns such as brake noise, brake judder or brake dragging
If you encounter a customer complaint for any one of these symptoms, refer to the following information to understand why symptoms may occur, and to better assist the customer in resolving their specific brake concern…
- Some customer's might state that they notice fluid or oil leaking/dripping on the ground when the vehicle…
Some customer's might state that they notice fluid or oil leaking/dripping on the ground when the vehicle is parked. For this concern, inspect the vehicle for any trace of a fluid or oil leak and use the following…
NHTSA lists 289 bulletins for this year; the 12 newest are shown here.
Other years of this model
Questions and answers
What are the most common problems with the 2018 Mazda CX-9?
Owner complaints to NHTSA most often mention: engine, electrical system, powertrain. Total complaints: 128. The most frequent symptoms in complaint texts: overheating, coolant loss (45%), infotainment or screen glitches (12%), engine failure or replacement (9%).
How many service bulletins (TSB) were issued for the 2018 Mazda CX-9?
NHTSA lists 289 manufacturer service bulletins for this year. A bulletin tells dealers how to diagnose or fix a known issue; it is not a recall.
Should I buy a 2018 Mazda CX-9 from a US auction?
Owner complaints describe defects, not crash damage. Before bidding, check the components listed above and review the lot photos: VinWind builds a report of visible and hidden damage by VIN.
Other 2018 models
Read also
Sources: public NHTSA data (USA): service bulletins and owner complaints; YouTube: links to videos credited to their authors. Complaints are owner statements not verified by NHTSA, and describe defects rather than crash damage. Data updated 2026-11-04.