Dangerous cylinder deactivation trouble on 2018 CX-5 and 6 models

Newbie here. I've been looking at CX-5's and just discovered this thread. So supposedly a software change fixes the problem. My concern though is with the oil pressure valve that the PCM is controlling inside of the engine. Is this valve fail safe? Solenoids do fail, and should not be allowed to cause a crash if it does. Has anyone unplugged this valve from the PCM to see how the engine runs? It'd be nice if that's all it took to disable this feature... Thanks!
 
Yes, it's very interesting. From a logical point of view, unplugging one of the plugs from the cd connectors should result in system deactivation.

Until someone tries it on crashed M6 we won't find out.

I think, however, that the engine will enter emergency mode, the Japanese had to predict this, it is impossible that turning off this system would be so simple, and certainly will be accompanied by problems.

The control of the valves and the entire system itself is in the Power Control Module and it is very doubtful that anyone will easily modify the system and turn it off.

I am also interested in whether Mazda's original diagnostic IDS Spftware at dealer system can turn it off.
 
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2013 Mazda CX-5 Sport FWD Auto
People were able to disable Honda’s VCM by fooling the computer. VCM on a Honda is activated only when it’s at the appropriate operating temperature. By plugging a resistor into the temperature sensor, the signal can be altered to be about 8 degrees below this threshold. The temp reading is still high enough to not trigger a CEL. Presto, VCM disabled.
 

sm1ke

Work In Progress..
Moderator
Contributor
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Canada
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'18 CX-9 Signature
Mazda needs to keep a better handle on their suppliers. Ed
Always room for improvement. Here's hoping they learned from this, and are implementing additional QA measures (and switching suppliers).
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
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Plano, Texas, USA
Are the 2020 3's ok now? Considering one.

I may just opt for the CX-30 which only has it on the Premium trim.
Yes, in the US you still can find SkyActiv-G 2.0L、some 2.5L、or 2.5T which doesn’t have cylinder deactivation. The 2.5L on lower trim CX-30 is non-CD like you said. Personally I wouldn’t get any CD engines for long-term consideration.
 
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2018 CX-9 Sig
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2014 CX-5 GT
Are the 2020 3's ok now? Considering one.

I may just opt for the CX-30 which only has it on the Premium trim.
Not sure. If you look at people with the new Mazda 3, the issue seems even worse:

 
Not sure. If you look at people with the new Mazda 3, the issue seems even worse:

The Mazda 3 has had a ton of teething issues, related to many parts of the car.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Is it possible to deactivate the cylinder deactivation system? Ed
I don’t believe there’s someone who has figured it out how to disable Mazda’s cylinder deactivation like Honda’s VCM system. Even if there’s a way, most likely it can only be a software solution. But the root problem is still there on Mazda’s cylinder deactivation system, the rocker arm can be fallen if the oil pressure isn’t right to feed the HLA. It’s because there’s nothing physically to prevent the rocker arm falling as a fail-safe device like most others do.
 
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2018 CX-9 Sig
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2014 CX-5 GT
The Mazda 3 has had a ton of teething issues, related to many parts of the car.
I have driven a 2.5 NA in the CX-5 and could not feel the CD in action. In my old Odyssey, you felt it as a clunk. That seems to be what the people in the new 3 notice.
 

Avoidin Deer

Zoom Zoom, baby
Contributor
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Central Virginia
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2019 CX-5 Reserve
I ended up buying a CX-30 without the CD. Only the Premium trim level of the CX-30 has the CD and I went with the Select.
I wouldn't blame anyone for avoiding it. I would have not purchased a car with Direct Inject had there been any selection to speak of.
 
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CX-5 II 2.5L Skycruise AWD AT 192hp
The software update (since 2018, my CX-5 2.5L, non-turbo) seems to have cured this problem definitely, no more complaints about this issue on the different European CX-5 forums .
I think that the Mazda engineers solved this problem correctly.
 
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‘17 CX9 & ‘19 6 GS
yrwei52 I believe you made the right choice in not buying the 2018. Mine is on a 3 year lease with 2 years remaining. I have tried to get out of the lease by moving up to the new CX-5 reserve with the Turbo at the same dealership that I bought the 18 at but it is going to cost me an arm and a leg to get out of it. So I wait for a couple years and hope that the new engine and PCM actually fixes the problem. So far so good but we will see. If nothing else I would like to see Mazda at least change the logic that puts the car into limp mode at those higher RPMs. That may make the car safer at least. But I have argued that point ad nauseam with Mazda and can't seem to make them change it.
Just going thru the thread about this Cyl deactivation issue now that I have just bought a 2019 6 and dealer claims to have reprogrammed the PCU on my vehicle last week prior to delivery/pick up. Just wanted to know your experience since they've replaced the engine if you are still having an issue now that it's been almost a year ever since...appreciate your feedback and hopefully Mazda has solved the issue with just the reprogramming...
 

Avoidin Deer

Zoom Zoom, baby
Contributor
:
Central Virginia
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2019 CX-5 Reserve
Just going thru the thread about this Cyl deactivation issue now that I have just bought a 2019 6 and dealer claims to have reprogrammed the PCU on my vehicle last week prior to delivery/pick up. Just wanted to know your experience since they've replaced the engine if you are still having an issue now that it's been almost a year ever since...appreciate your feedback and hopefully Mazda has solved the issue with just the reprogramming...
There have been a handful of people here who have had the software update done to their cars. Some reported increased performance/increased mileage. Others reported the opposite. General opinion on the reason behind this is that the update requires disconnecting the battery, which resets "driver learning."

But no one after getting the update has come back and reported any CD malfunctions (throwing codes, limp mode, etc.) Nor has anyone here with a later model CX-5 (updated before taking ownership) reported any CD issues that I've seen.
 
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‘17 CX9 Sig/ ‘19 6
There have been a handful of people here who have had the software update done to their cars. Some reported increased performance/increased mileage. Others reported the opposite. General opinion on the reason behind this is that the update requires disconnecting the battery, which resets "driver learning."

But no one after getting the update has come back and reported any CD malfunctions (throwing codes, limp mode, etc.) Nor has anyone here with a later model CX-5 (updated before taking ownership) reported any CD issues that I've seen.
That is good to know (in a way reassuringly) that there hasn’t been anymore reported cases after the software update and I assume your experience so far with the new engine/reprogrammed ECU that all is also good. Am not too worried abt the mileage whether increased or decreased as I myself don’t have any basis for comparison since I’ve gotten the vehicle with an updated software already. As long as the CD is working fine and won’t produce any error codes/mechanical failures and going into limp mode then am not too worried after all Mazda has a 5yr powertrain warranty. Thanks for the feedback!
 

Avoidin Deer

Zoom Zoom, baby
Contributor
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Central Virginia
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2019 CX-5 Reserve
That is good to know (in a way reassuringly) that there hasn’t been anymore reported cases after the software update and I assume your experience so far with the new engine/reprogrammed ECU that all is also good.
Just by way of information, I have the turbo version of the 2.5L, which does not have cylinder deactivation. That engine is in the Reserve and the Signature trims. So my experience is strictly second-hand from what I read here and elsewhere.

But all's been quite since the updates. And as you said, you have 5 years of coverage on Mazda's dime.
 
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