Dangerous cylinder deactivation trouble on 2018 CX-5 and Mazda6 models

[jjm86m]

I'd wager that 95% of the population doesn't even know what the tachometer is showing, let alone understand what RPM is or what's required to have the engine go into limp mode. They'd know what "floor it until you're scared" means, but that's about it.

...

TLDR, asking someone to hold revs or keep above a certain RPM for a certain amount of time is like nerdy tech jibberish.

...

Mazda's fix appears to just prevent limp mode from occurring during a lean condition (likely just reduces power instead) because, the same people I described above, won't ever notice. Visually inspecting every Cx5 and replacing entire engines might bankrupt Mazda. Just reduce power (or ignore) for the 0.01% of the population who would ever encounter this lean condition instead of triggering a potentially dangerous limp mode. You now have your most cost effective "fix". Problem solved.

Fair point overall for the RPM. However I'd counter and say that anyone on a forum for a cx5 might already be in the nerdy crowd and could hold a RPM lol.

As far as the limp mode, PCM, rocker arm. It does seem as though Mazda took the approach of, there aren't any rocker arms that would have fallen off bc we would've already heard about it. So therefore any cars coming in for the recall are still OK. Not great logic but probably defend-able in court if it ever went that far.

 

[MyFirstMazda]

Ed, the whole reason GoHawks and I are unhappy with the "fix" is because the dealership and ultimately Mazda Corporate are only fixing CX5's that don't have any issues. If you already have a rocker arm that is fallen off the fix to the recall is only masking the issue. The dealership flashed my PCM and the limp mode issue went away. But at the end of the day it only masked the problem because the rocker arm had already fallen off and a software update didn't magically reinstall the rocker arm. I tried multiple times to get the engine to limpmode post PCM update without any success and yet there was still a floating arm inside the engine.

IMO it isn't foolish to drive at over 5000 RPM or even up to redline. You don't have to be screaming down the highway at 5000RPM. You can easily hit 5000 at under 30mph. Like I mentioned in a previous post. Be smart about where you try this. You don't need to be mechanical minded to have a little common sense.

Also, For the record my limp mode did not occur until 6000-6200 RPM. Details are documented in other posts on this thread.

The rev test may not show that the rocker is off. Jjm86m it might be possible that your car wouldn't have gone into limp mode again without that initial reprogramming, if the exact conditions were not met, including the location of the loose rocker. Maybe when it went into limp mode, the loose rocker interfered with the valve assembly next to it. When the rocker lets loose it must go like a pin ball until it settles in a spot that it can't move.

 

[MyFirstMazda]

I think what Mazda should do to check the valves is to blow air into the combustion chamber from the spark plug hole after rotating the crankshaft to a position when the valves should be open. If a certain resistance to the blown air is found then one or more valves would be closed when they should be open. Then they don't even need to remove the valve cover.

 

[csdstudio78]

Fair point overall for the RPM. However I'd counter and say that anyone on a forum for a cx5 might already be in the nerdy crowd and could hold a RPM lol.

As far as the limp mode, PCM, rocker arm. It does seem as though Mazda took the approach of, there aren't any rocker arms that would have fallen off bc we would've already heard about it. So therefore any cars coming in for the recall are still OK. Not great logic but probably defend-able in court if it ever went that far.

That's a good point as well. I thought about something else, this missing rocker arm would only lead to starvation of air, aka rich, not a lean condition. There's no chance for engine damage with a stuck valve so there's no further risk for Mazda ignoring the permanently closed valve. But if they start proactively searching for missing rocker arms, they might corner themselves into an expensive situation where that rocker arm may never cause an issue anyway.

The OP said there's no way to know how long his rocker arm had been off and that it could have been like that for thousands of miles. Again... minimum risk, so why spend the money to fix something that's not actually broken (from their perspective: not causing any serious problems). Missing 1 out of 8 intake valves = roughly 12.5% power loss at full throttle and high rpm. Hardly anyone's butt dyno would even notice that. In a near 4k lb vehicle, 187hp is already slow.

PCM update: "Just ignore the silly error." Mazda risks nothing by going this route... we'll see I guess.

 

[jjm86m]

Right or wrong, when you look at it from a business perspective you'll see why Mazda is doing what they are doing.

2018 USA CX5 Sales Numbers: 150622
2018 USA Mazda 6 Sales Numbers: 30038

Total US Sales: 181560

Cost to remove and check valve cover: $220 (as quoted to me from the dealership and what was paid from mazda corporate to dealership)

Reasonable Assumption: 10% of your vehicles sold need checked
Cost to Mazda Corporate to USA Dealership for valve check: ~$4million

Worst case assumption: All vehicles need checked
Cost to Mazda Corporate to USA Dealership for valve check: ~$40million

Cost of tweaking PCM Software and releasing it to dealership: Presumably significantly less than $4 Million

Some risk analyst took the 26 cases worldwide and ran the probabilities against all vehicles sold world wide and gave a report saying the cost/benefit to check valve covers isn't worth it.Management/Engineers review and approve. A PCM update makes them less liable as well so corporate's risk goes down even more. If in the case someone dies because of this then the settlement would still be equal to or less than checking every car. Its a cold way of looking at it but it's business. Looking out for bottom line.

 

[NelsonLewis]

Right or wrong, when you look at it from a business perspective you'll see why Mazda is doing what they are doing.

2018 USA CX5 Sales Numbers: 150622
2018 USA Mazda 6 Sales Numbers: 30038

Total US Sales: 181560

Cost to remove and check valve cover: $220 (as quoted to me from the dealership and what was paid from mazda corporate to dealership)

Reasonable Assumption: 10% of your vehicles sold need checked
Cost to Mazda Corporate to USA Dealership for valve check: ~$4million

Worst case assumption: All vehicles need checked
Cost to Mazda Corporate to USA Dealership for valve check: ~$40million

Cost of tweaking PCM Software and releasing it to dealership: Presumably significantly less than $4 Million

Some risk analyst took the 26 cases worldwide and ran the probabilities against all vehicles sold world wide and gave a report saying the cost/benefit to check valve covers isn't worth it.Management/Engineers review and approve. A PCM update makes them less liable as well so corporate's risk goes down even more. If in the case someone dies because of this then the settlement would still be equal to or less than checking every car. Its a cold way of looking at it but it's business. Looking out for bottom line.

Yep Yep!

 

[murky]

I think what Mazda should do to check the valves is to blow air into the combustion chamber from the spark plug hole after rotating the crankshaft to a position when the valves should be open. If a certain resistance to the blown air is found then one or more valves would be closed when they should be open. Then they don't even need to remove the valve cover.

Clever

 

[csdstudio78]

Right or wrong, when you look at it from a business perspective you'll see why Mazda is doing what they are doing.

2018 USA CX5 Sales Numbers: 150622
2018 USA Mazda 6 Sales Numbers: 30038

Total US Sales: 181560

Cost to remove and check valve cover: $220 (as quoted to me from the dealership and what was paid from mazda corporate to dealership)

Reasonable Assumption: 10% of your vehicles sold need checked
Cost to Mazda Corporate to USA Dealership for valve check: ~$4million

Worst case assumption: All vehicles need checked
Cost to Mazda Corporate to USA Dealership for valve check: ~$40million

Cost of tweaking PCM Software and releasing it to dealership: Presumably significantly less than $4 Million

Some risk analyst took the 26 cases worldwide and ran the probabilities against all vehicles sold world wide and gave a report saying the cost/benefit to check valve covers isn't worth it.Management/Engineers review and approve. A PCM update makes them less liable as well so corporate's risk goes down even more. If in the case someone dies because of this then the settlement would still be equal to or less than checking every car. Its a cold way of looking at it but it's business. Looking out for bottom line.

lol. Such is life. Individually, we're but a small, insignificant variable in a large equation of risk.

 

[joemazdacx5]

so, now it sounds like some are saying to not do this pcm update ! since it masks the issue..........

wish I kept my good old reliable 99 ranger.... for a few more years........

 

[cz5gt]

I think it was mentioned that the PCM does not mask or hide anything.

What some of the affected people are suggesting is that it would be a good idea to have a mechanical/visual check on the rocker arms to confirm or deny if the main issue has happened already. All that apart from the pcm update.

 

[MyFirstMazda]

so, now it sounds like some are saying to not do this pcm update ! since it masks the issue..........

wish I kept my good old reliable 99 ranger.... for a few more years........

No, do the update. Mazda says it fixes the potential issue. Then you can either pay the dealer to do a visual check, or just drive the car. Personally I don't want to pay to have mine checked, if I have a rocker arm out of place I will find out sooner or later.

 

[yugrus]

If you already have a rocker arm that is fallen off the fix to the recall is only masking the issue. The dealership flashed my PCM and the limp mode issue went away. But at the end of the day it only masked the problem because the rocker arm had already fallen off and a software update didn't magically reinstall the rocker arm. I tried multiple times to get the engine to limpmode post PCM update without any success and yet there was still a floating arm inside the engine..

Holly cow. Do you guys realize what this means, if it really comes down to it?

 

[ruthrj]

Huh. Not a fan of that at all if it*s true. I would really hope that the CEL thrown at high rpm wasn*t consistently reproducible. Not to open a can of worms, but Mazda did something similar when transmission fluid sensors in the transmission were dirty. The transmission was flashed in those cases to raise the threshold of the sensor before signaling an error. Masking dirty fluid?

 

[Go Hawks]

Ed, the whole reason GoHawks and I are unhappy with the "fix" is because the dealership and ultimately Mazda Corporate are only fixing CX5's that don't have any issues. If you already have a rocker arm that is fallen off the fix to the recall is only masking the issue. The dealership flashed my PCM and the limp mode issue went away. But at the end of the day it only masked the problem because the rocker arm had already fallen off and a software update didn't magically reinstall the rocker arm. I tried multiple times to get the engine to limpmode post PCM update without any success and yet there was still a floating arm inside the engine.




So this just reinforces our belief that they need to be doing a visual inspection. If they do indeed disable limp mode with the reflash, what is their (Mazda*s) motivation for doing so? Don*t get me wrong, I am in favor of not having the vehicle go into limp mode under a misfire condition at high engine rpm. But if your car has the rocker arm already off, Mazda knows this recall work will not fix this issue. Let*s assume most of these cars are still under warranty. So now you are driving around with a dislodged rocker arm that could possibly move into a compromising position amongst the other operating valves. If this happens and it causes a catastrophic failure will Mazda cover this repair if your vehicle is now out of warranty? I would bet not. And you as the owner will have a heck of a time proving that it was an existing condition left over from before your recall work done 20,000 miles ago.

 

[cz5gt]

It would be highly unlikely one would drive 20,000 miles without anomalies presenting due to a fallen rocker arm.

Don't understand why people claim pcm firmware update disables limp mode and error detection when the recall openly states it fixes oil pressure on the inlet valves control mechanism in reference to the CD on/off.

 

[velocityc6]

As I said before, glad we purchased our 2018 Touring CPO with a 7yr/100k warranty. If the PCM update is only a "mask" and doesnt do anything positive to stop the rocker from falling off, at least we have many years of driving to see if the motor grenades itself.

So I ask this from the "masking" folks. Do ALL these engines with CD even with the PCM update, even those being installed at the factory today. Is this a FATAL design flaw which has no cure minus some redesign work.

If its just a "mask" then it would mean even a brand new 0 mile 2.5L could/will have that rocker arm fall off.

 

[velocityc6]

It would be highly unlikely one would drive 20,000 miles without anomalies presenting due to a fallen rocker arm.

Don't understand why people claim pcm firmware update disables limp mode and error detection when the recall openly states it fixes oil pressure on the inlet valves control mechanism in reference to the CD on/off.

I agree, too many speculating that Mazda is actually compounding the problem by further hiding a potential engine failure. That would turn this into a full blown cover up.

I dont believe this is the case, im with you that the PCM update corrects the issue which may cause a rocker arm displacement.

 

[yrwei52]

It would be highly unlikely one would drive 20,000 miles without anomalies presenting due to a fallen rocker arm.

Don't understand why people claim pcm firmware update disables limp mode and error detection when the recall openly states it fixes oil pressure on the inlet valves control mechanism in reference to the CD on/off.

This's based on their personal experience when Mazda did only PCM firmware re-flash without checking their fallen rocker arm. Yeah the new code should raise the oil pressure to hydraulic lash adjusters to prevent rocker arms falling, but it could also have disabled the limp mode and CELs. At least this's what those who had experienced.

My personal experience on recalls and TSBs for my CX-5 by Mazda definitely is not a good one. The replacement struts on liftgate recall are worse on quality; fuel-filler pipe recall looks like a temporary patch job. And EPB dragging TSB has several revisions started with EPB control module updates in firmware, eventually revised rear brake calipers have to be introduced.

I hope this rocker arm recall won't become another EPB dragging TSB.

 

[AlexSR]

It seems recalls are going to start in Europe according to a German website, but still is not on RAPEX:

"Mazda hat aktuell vier Rckrufaktionen angekndigt. Volumenmig umfasst ein Problem der Motorsteuergerte der Modelle 3 (BP), CX-5 (KF) und 6 (GL) mit europaweit 57.896 Einheiten aus dem Produktionszeitraum 20.06.2017 bis 23.05.2019 die meisten Fahrzeuge. Bei den Motorsteuergerten (PCM) kann die Software, die den hydraulischen Ventilspielausgleich steuert, beim bergang von der Zylinderabschaltung in den Normalbetrieb whrend der Fahrt fehlerhaft arbeiten. Infolgedessen kann ein Kipphebel des Einlassventils aus der Position geraten und mit inneren Motorteilen in Kontakt kommen. Es besteht die Gefahr von Fehlzndungen des Motors und Leistungsverlust."

Let's see how swift is Mazda in each country, certainly less than in Japan or in the US.

 

[dwill]

Guess its an official recall now.

https://www.freep.com/story/money/cars/2019/07/10/mazda-recall-engine-stall/1691547001/

Doesnt affect the turbo engine, right?