Faulty Transmission
2012 Mazda CX-9
This problem may be covered under warranty. Ask your Mazda dealer.

CarComplaints.com Notes: The only area of real concern for 2012 Mazda CX-9 owners is the brake booster.
In 2014, Mazda extended the warranty on the 2007-2013 CX-9 brake booster to 7 years / 90,000 miles. However this extended warranty has expired for most CX-9 owners, so buyer beware.
This Mazda CX-9 brake booster failure isn't terrible in terms of repair cost — it "only" costs $550 average to fix. However it is a safety issue when the brake booster fails as it increases stopping distance. Owners have reported having to stomp on the brake pedal, & crashes/injuries have been reported due to this CX-9 brake booster defect.
8.7
pretty bad- Typical Repair Cost:
- $3,200
- Average Mileage:
- 56,000 miles
- Total Complaints:
- 3 complaints
Most Common Solutions:
- faulty tcm (1 reports)
- forced to install new trans and ptu (1 reports)
- replace transmission (1 reports)
transmission problem
Helpful websites
- No one has added a helpful site for this 2012 CX-9 problem yet. Be the first!

A D V E R T I S E M E N T S
Worn spine gear btw trans and power trans unit.
Dealer originally replaced the power trans unit (ptu) within warranty in 2015 due to oil leak, but trans shop that did the second ptu replacement and also a new trans replacement said the trans should have been also replaced in 2015. But the dealer did not do this and I didn't know enough to ask about it. CX9's are noted for this ptu failure. The new problem was a result of severe wearing of spline gear in ptu and trans units. Spline gear joints with ptu and trans are a very bad design flaw. Harder metal or some different design should have been used. And the ptu oil is very hard to drain and refill. No maintenance is listed for this but it eventually burns out bc of being too close to hot parts, like exhaust lines and or the trans. I made it a practice to drain and refill the ptu every 30000 miles or about 3 years. But this didn't prevent the spline gear wear problem.
This model year has been recalled for lower control arm issues (I think potential corrosion due to salt on roads), rear suspension issue (I forget what it was), and maybe an airbag issue. My brake booster was also replaced under warranty due to a leak.
- Charles B., Reading, US