2016~2023 CX-9 slower after dealer visit

Fawiek

Member
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2018 CX-9 GT
So I've been really looking to figure this out, maybe some input.

I have a 2018 cx9 GT-- lovely vehicle.

When I just got it, I was so surprised by the torque and it's ability to put you on your seat at nearly any speed.

After breaking in the engine, I did a few 0-60 pulls and got between 6.9-7.2 seconds consistently! Right on the reported speed of this vehicle.

About a year after getting the car ,(brand new) I carried it to Mazda for an oil change. The took it upon themselves to update the PCM (engine computer).

I noticed immediately the car felt different and underpowered driving home from the dealer.
Did a few pulls 0-60 using the same app, same roads and using 94 gas.
I'm now getting at best 7.9-8.5 seconds 0-60.

Gas is 94 octane and I just did a fresh oil change to Castrol edge.

Just last week another pcm update was available to I carried it in thinking maybe it'll be better-- nope, still feels sluggish. Car has 68k kms now with newly installed plugs from the dealer, OEM.
New pulls reveal the same numbers to 60.
Tried sports mode, traction off etc and various combinations-- still feels slower than when I just got it.

Note, I tried to keep an variables the same to repeat it he results fairly.

Exact same result, 7.99-8.5 seconds to l from 0-60, a full second more than what I recall when now getting it.

Any ideas?
 

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So I've been really looking to figure this out, maybe some input.

I have a 2018 cx9 GT-- lovely vehicle.

When I just got it, I was so surprised by the torque and it's ability to put you on your seat at nearly any speed.

After breaking in the engine, I did a few 0-60 pulls and got between 6.9-7.2 seconds consistently! Right on the reported speed of this vehicle.

About a year after getting the car ,(brand new) I carried it to Mazda for an oil change. The took it upon themselves to update the PCM (engine computer).

I noticed immediately the car felt different and underpowered driving home from the dealer.
Did a few pulls 0-60 using the same app, same roads and using 94 gas.
I'm now getting at best 7.9-8.5 seconds 0-60.

Gas is 94 octane and I just did a fresh oil change to Castrol edge.

Just last week another pcm update was available to I carried it in thinking maybe it'll be better-- nope, still feels sluggish. Car has 68k kms now with newly installed plugs from the dealer, OEM.
New pulls reveal the same numbers to 60.
Tried sports mode, traction off etc and various combinations-- still feels slower than when I just got it.

Note, I tried to keep an variables the same to repeat it he results fairly.

Exact same result, 7.99-8.5 seconds to l from 0-60, a full second more than what I recall when now getting it.

Any ideas?

Just spitballing here, but have you checked the engine air filter? I'm guessing no CELs, but are you able to check for trouble codes with an OBD2 reader?

The engine air filter is a reach because normally, if it's the cause of the problem, it's because it gradually gets clogged and restricts air flow. But if if happened right after the PCM update, I would also see if it is possible for the dealer to "roll back" the PCM's firmware to the version you originally had.

I was not aware of any PCM updates and to my knowledge, my car (also a 2018) is still on the original version it came with.

Something else to check is the tire PSI. Higher PSI results in better fuel economy but worse traction. Maybe the dealer over-inflated the tires when they gave the car back to you?
 
Just spitballing here, but have you checked the engine air filter? I'm guessing no CELs, but are you able to check for trouble codes with an OBD2 reader?

The engine air filter is a reach because normally, if it's the cause of the problem, it's because it gradually gets clogged and restricts air flow. But if if happened right after the PCM update, I would also see if it is possible for the dealer to "roll back" the PCM's firmware to the version you originally had.

I was not aware of any PCM updates and to my knowledge, my car (also a 2018) is still on the original version it came with.

Something else to check is the tire PSI. Higher PSI results in better fuel economy but worse traction. Maybe the dealer over-inflated the tires when they gave the car back to you?
I'll check to see if any codes come up, I should as I'll be out of warranty in a couple months!
Just had the plugs replaced at 64k kms, noticed better fuel economy. Averaging about 7.0L/100 kms, mainly highway obviously.

The air filter was changed out when I mentioned this to the service at Mazda (about 24k km), same result. I'll check on it again though to see if it could be that but unlikely as the problem persisted after the first air filter change.

The shop I go to switch my winters (mounted on diff rims) tops up the air, this gets done twice a year. I'll give this a look as well because I've been surprised by easy fixes in the past.

Bought this car for the space, agility (acceleration) and looks. If I'm losing a second then I think with everything considered (service issues Mazda Canada' seems to minimize or punt off like it's normal or no big deal) I'll likely sell since there is a shortage of used cars ATM.
 
I'll check to see if any codes come up, I should as I'll be out of warranty in a couple months!
Just had the plugs replaced at 64k kms, noticed better fuel economy. Averaging about 7.0L/100 kms, mainly highway obviously.

The air filter was changed out when I mentioned this to the service at Mazda (about 24k km), same result. I'll check on it again though to see if it could be that but unlikely as the problem persisted after the first air filter change.

The shop I go to switch my winters (mounted on diff rims) tops up the air, this gets done twice a year. I'll give this a look as well because I've been surprised by easy fixes in the past.

Bought this car for the space, agility (acceleration) and looks. If I'm losing a second then I think with everything considered (service issues Mazda Canada' seems to minimize or punt off like it's normal or no big deal) I'll likely sell since there is a shortage of used cars ATM.

So who have you talked to about this issue so far? Sounds like you've already brought this up with the dealer, who seemed to write it off as normal (it definitely isn't). Have you spoken with another dealer and escalated to Mazda Canada?

At first I thought that the dealer just did an oil change and a PCM update. But then you mentioned that they changed the engine air filter too? Or did they do that during the second visit, when they updated the PCM again?

Do you have a copy of the invoice(s) to show what version of the PCM they updated it to?


Check your car for trouble codes (or bring it to a shop that can read the codes for you for free). Then I'd suggest checking the engine air filter yourself, to make sure that it is installed correctly. I'd also check your tire PSI.
 
It’s a long shot but you could check for this issue.


Someone with the turbo engine had a low compression issue as well (I think on the mazda 6 forums). This could be worth looking into.

Hard to pinpoint a single cause. It could be awd being slower to react, it could be brake drag, it could be carbon build up, etc.

Also the car would have better 0-60 time on winter rims in theory, (those 20” are heavy) but I assume your previous runs were in summer as well since you said you kept conditions the same.

What app are you using for your 0-60 runs? I have a 2018 as well but don’t fill up with 94 so I can’t really compare.
 
I recently had some transmission issues and had to force the dealer to update both my TCU and ECU. There were 2 TSB's issued, attached, for the exact issues I was having but my 2017 CX-9 VIN was not included in one them. The software update fixed both issues and my vehicle has not lost any power.

These are the software versions I was on and am on now.
Old:
Engine control unit
Manufacturer ECU software number: PYFM-188K2-H
Transmission control unit
Manufacturer ECU software number: PYFM-21PS1-C

New:
Engine control unit
Manufacturer ECU software number: PYFM-188K2-R
Transmission control unit
Manufacturer ECU software number: PYFM-21PS1-D
 

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I recently had some transmission issues and had to force the dealer to update both my TCU and ECU. There were 2 TSB's issued, attached, for the exact issues I was having but my 2017 CX-9 VIN was not included in one them. The software update fixed both issues and my vehicle has not lost any power.

These are the software versions I was on and am on now.
Old:
Engine control unit
Manufacturer ECU software number: PYFM-188K2-H
Transmission control unit
Manufacturer ECU software number: PYFM-21PS1-C

New:
Engine control unit
Manufacturer ECU software number: PYFM-188K2-R
Transmission control unit
Manufacturer ECU software number: PYFM-21PS1-D
Thanks.. good to know the update didn't cause any power loss.

There were too many variables in the post regarding the OP' s particular situation such as:

What was the OPs mileage when he took it to dealer for first software update?

OP was @ 68k km or equivalent 43k miles @ time of posting. Engines lose some power with age...sort of a bell curve.
Although a properly maintained engine should perform relatively close to new, it never will be new.

OP had sparks changed. Where the same make and brand used and gapped correctly?

Who knows, it could have been from dealer reprogram(it could have been the Mazda program itself(conservative tweak to prolong engine life, perhaps) or maybe(don't know if it's possible), but maybe the dealer tweaked the computer on purpose so OP would come back.

Or it could have been dealer made a mistake(we all make mistakes) and used wrong weight oil which maybe accelerated engine wear. That's why I always do my own or during busy times of life, have trusted mechanic do it.

Or it could have been a faulty engine. I've seen many posts on here regarding engine problems.

Also, OP put 43k miles on vehicle in approx. 3 to 3.5 years. Which is approx. 12k to 14 k miles per year yet took to dealer for oil change after 1 year so would that be 14 k miles before first oil change? Or did they change in between? Or did they not properly maintain oil intervals?

OP should have had a trusted mechanic do a compression test right after felt car didn't feel right.

There were just too many variables and too many things that could have caused power loss.

We could sit here all day and add thing to the list that could have contributed to power loss but wouldn't be productive at this point.

If OP had taken to his own mechanic for a look he may have been closer to an answer.

Its hard to second guess in hindsight.
 
Thanks.. good to know the update didn't cause any power loss.

There were too many variables in the post regarding the OP' s particular situation such as:

What was the OPs mileage when he took it to dealer for first software update?

OP was @ 68k km or equivalent 43k miles @ time of posting. Engines lose some power with age...sort of a bell curve.
Although a properly maintained engine should perform relatively close to new, it never will be new.

OP had sparks changed. Where the same make and brand used and gapped correctly?

Who knows, it could have been from dealer reprogram(it could have been the Mazda program itself(conservative tweak to prolong engine life, perhaps) or maybe(don't know if it's possible), but maybe the dealer tweaked the computer on purpose so OP would come back.

Or it could have been dealer made a mistake(we all make mistakes) and used wrong weight oil which maybe accelerated engine wear. That's why I always do my own or during busy times of life, have trusted mechanic do it.

Or it could have been a faulty engine. I've seen many posts on here regarding engine problems.

Also, OP put 43k miles on vehicle in approx. 3 to 3.5 years. Which is approx. 12k to 14 k miles per year yet took to dealer for oil change after 1 year so would that be 14 k miles before first oil change? Or did they change in between? Or did they not properly maintain oil intervals?

OP should have had a trusted mechanic do a compression test right after felt car didn't feel right.

There were just too many variables and too many things that could have caused power loss.

We could sit here all day and add thing to the list that could have contributed to power loss but wouldn't be productive at this point.

If OP had taken to his own mechanic for a look he may have been closer to an answer.

Its hard to second guess in hindsight.
Thanks for the info.

Plugs were changed at the dealer with their products.

Oil always been Castrol edge 5w30 and changed at the appropriate times ie every 8000kms, again at the dealer.

The change was literally overnight after the vehicle was in the shop and they told me they updated it as it was available-- your welcome. I didn't want to do that as I prefer to let these software updates to be well tested before I am willing to use it ..

At the time, the tires were the same (stock falkens) as I drove back home and the next few months etc.

The air filter was changed (first thing I tried after the sluggish feel).

The EPA remains the same on my highway runs between 6.6-7.1L/100kms, which is really good for a three row. Just don't know why it's not as nimble as it use to be. No codes either btw.

Anyone know if the sports mode with traction off does anything for quicker speed in general? I personally kept it the same, trac off and regular mode to achieve 7.0 second 0-60 runs... Meh... Kinda over it, looking to sell possibly 🤷🏽‍♂️
 
Sport mode changes the shift points. The transmission will stay in a gear longer while the engine runs at a higher, more sporty, rpm before shifting up to the next gear.
 
Speaking of sport mode, does driving with it on all the time have any adverse effects in the long run?
 
Speaking of sport mode, does driving with it on all the time have any adverse effects in the long run?
I use it alot, not all the time, but about 30%.

Not an engineer, but imo, would think it might be better for transmission as tranny isn't slipping in and out of gears as much. And with everything computerized, would think computer should stop any shift points that would be detrimental to vehicle, engine, etc.

Regular mode/gear with all the downshift and upshift may cause more transmission wear.

Engine wear is probably about similar...as assuming that engineers wouldn't let sport mode run engine at high rpms that could damage engine.

Edited:

According to some websites, using it all the time could put extra strain on the engine and cause engine to wear slightly faster than normal. So might want to get in habit of using only when needed and turn off on highway/level roads.

The only thing that might suffer is fuel economy and oil longevity if run sport mode 100% all time then might need to fill gas tank more often and do oil changes more frequently.
 
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Getting off-topic, but there is a misconception that higher revs are bad for engines. While we may never know what each specific engine breaking point or weak point is in advance (wether it is from total number of revolution or high loads), typically the hardest thing for an engine is wide-open throttle, regardless of the RPM. That is where you are putting the highest load on the engine components.

Where this become interesting is that there is 2 ways to create the same amount of power, you either make one hard push or multiple small push. So for example, to create the same power output, you can either give a lot of gas at low RPM (Wide Open Throttle at 2500 RPM for example) or a little bit of gas at higher RPM (mid-throttle at 4000RPM). The last option is in most cases easier on the engine.

So using the transmission gearing to keep revolutions downs is hard on engine, but car companies designs their cars that way because it provides better fuel economy, is quieter and most people don't like to hear their engine revs.

Also, my sport mode kind of "shut off when cruising", if I start cruising, it does go back to a normal gear. I would have to retry it, but I think if I was in sport mode on the highway, it would be in the same gear as normal mode until I wanted to accelerate.
 
I use it alot, not all the time, but about 30%.

Not an engineer, but imo, would think it might be better for transmission as tranny isn't slipping in and out of gears as much. And with everything computerized, would think computer should stop any shift points that would be detrimental to vehicle, engine, etc.

Regular mode/gear with all the downshift and upshift may cause more transmission wear.

Engine wear is probably about similar...as assuming that engineers wouldn't let sport mode run engine at high rpms that could damage engine.

Edited:

According to some websites, using it all the time could put extra strain on the engine and cause engine to wear slightly faster than normal. So might want to get in habit of using only when needed and turn off on highway/level roads.

The only thing that might suffer is fuel economy and oil longevity if run sport mode 100% all time then might need to fill gas tank more often and do oil changes more frequently.
The 'sport mode' mapping does not change the dynamics of the CX9 much. It holds gears a bit longer and down-shifts a bit earlier. Not dramatic.

Given 2.5T was designed for lots of low-end power/torque, the transmission has been programmed keep the torque converter locked for much of time time. The locked torque converter creates a pleasant, "direct" feeling between the engine and the drive wheels (as opposed to the 'slush box' feel you get from old fashion automatics).

The 2.5T runs out of steam by about 5K RPM. It's very diesel-like in that regard (not a bad thing, given it's in an SUV). A multi-stage turbo and multi-stage top end (think Honda VTEC or BMW VANOS) would be interesting but would have added serious expense.

If anything, using sport mode may extend the life of your brakes by a tiny bit as it allows the engine to do a little bit more engine breaking .
 
Car and Driver reported a 2mph trap speed increase as well as reduced 0-60 times and 1/4 mile ET's at 40,000 miles vs new, with their long-term turbo CX5 car. The 2.5T DPT engine gets faster with age, not slower. The same was observed on their long-term CX9 test car over 40,000 miles. Mazda made an excellent engine. Other cars they have tested with DI turbo engines, like Subaru's have done the opposite.
 
I have THE EXACT SAME ISSUE with my 2018 cx9 (70k). After a dealer visit for a routine oil change, where they overfilled my oil, the car was rougher and slower. After they fix the oil level, the performance improved a little bit but the car is not the same as before. It has lost its agility and responsiveness, the engine is definitely rougher, noisier, there are times it feels like it's straining, the turbo noise seems to be louder, cold performances even worse.

When I show it to the dealer they say that they can't feel anything is wrong with it. But the car does not feel and does not drive the way like it used to, I'm kind of at my wits and as to what to do.
 
Did you notice that they overfilled the oil immediately after the oil change? It's possible that it could have done some damage. If the dealer is absolutely unwilling to help, your next course of action should be to contact Mazda Corporate to open a case. Ensure that you have all of your maintenance records and document everything. See what they think about changing spark plugs (I believe you're due for your 2nd set of spark plugs at 80k mi), and maybe a compression test?
 
Immediately after I drove home, I noticed a serious drop in performance. I googled and they said to check oil level, it was way over and right then I called to book follow up. I have changed the plugs myself, drove a weak on premium, asked them to test everything. They said they updated firmware as well and checked all sensors. I will get all the documents and proceed to file a case.

The main issue is that it is all subjective, I feel a noticable difference, dealer says 'looks fine'. I wish there was some sort of conclusive measurable proof. Should I do a 0-60 test? Dyno test? I wish I had 2 2018 cx9s side by side to show them.
 
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Or this (well hopefully not, this looks like a bigger job to do)

Summary

Some customers may complain about a poor acceleration and rough idling or the CHECK ENGINE light ON with DTC P0301:00, P0302:00, P0303:00, P0304:00.NOTE: Only turbo engines are applicable; non-turbo engines are NOT applicable. In most cases, DTCs P030X stores, but sometimes not. Sometimes the CHECK ENGINE light does not recognize this engine concern. This is caused by the variable valve in the exhaust manifold seizing and causing the exhaust port to become hot and the exhaust valve seat to wear unevenly, resulting in compression leakage. To eliminate this concern, the design of the exhaust manifold has been modified.

 
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