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

cz5gt said:
if the rocker arm has fallen it doesnt really matter if the pcm hides anything.
The engine will not run normally from mechanical standpoint. You will notice it.
Then its a new engine time most probably for new cars. Dealers usually dont take the time and most may not have the personnel onsite to remove head from engine block, check valves, seats, clearances, send to repair shops, etc.
The easier route for new cars is new engine to be put it.
Click to expand...
No, based on those reports by people who have had the fallen rocker arm, they hardly felt much performance difference until the engine fell into the limp mode. That's the danger of this problem. No codes were generated after the PCM update with fallen rocker arm either which makes me believe the PCM update actually masks some codes too.

Further, replacing the entire engine definitely is a lot more expensive and complicated than simply put the fallen rocker arm back to the position. The mechanic at the dealer has open the valve cover checking the falling rocker arm, it's a piece of cake to put the fallen rock arm back once he/she spotted the rocker arm has fallen.
 
Mazda is being interested in what if any scaring or damaged is noticeable. Probably part of an in depth investigation. Good to hear Mazda is taking this seriously Ed
 
Avoidin Deer said:
I was reading some of the Mazda Mfr Communications on the NHTSA website. One of them spoke of issues with Powertrain Control Modules (PCMs) made by Mitsubishi. Makes me wonder if they subbed these out to anyone else.
Click to expand...
Mazda so far claimed it's the PCM programming issue which is adjusting the oil pressure improperly during the cylinder deactivation transition. Mitsubishi is the EPROM supplier who burns the software code into it. Mitsubishi takes only the software code from Mazda, can't blame the problem on them.
 
CD failure rate:

The question we all want to know is how rare or widespread this CD related failure is.
I have been searching the internet to see if there are reports of Mazda CD failures associated with the 6 and the CX-5 from News outlets, but nothing came up beside forum discussions, this site included. So does this mean the problem is rare?

I came across a Consumer Report Used Cars magazine today and CR gave the 6 and the CX-5 both an "Excellent" (highest) rating for reliability across all categories including Engine Minor and Engine Major for model year 2018. So does this mean the problem is rare?

Let me crunch some sale figures relative to the number of reported failures to get an idea. To be clear, my assumption may not be correct, those that are concerned can chime in.

Go Hawks first reported the CD issue in his original post dated 5/3/19 and he said "For the year model 2018, Mazda added cylinder deactivation to the engines that are installed in both the CX-5 and the Mazda 6 models. Unfortunately this system is what caused the trouble for us and, at last count, at least 26 other customers that Mazda has confirmed"

Assumptions:
1. I don't know if 26 failures included both CX-5 and 6, but let's assume 26 are all CX-5 failures (worse case).
2. 26 failures are nationwide (I can't imagine this many failures reported at one dealership Go Hawks went to)
3. We know CD was introduced beginning model year 2018 and after and since Go Hawks OP was 5/3/19, I will use March 2019 as a cut-off date to calculate sales figures.

Sales figures for CX-5:
2018: 150,622 units sold (according to "Car and Driver")
Jan 2019: 10,652
Feb 2019: 13,377
Mar: 13,465
Total: 188,116 units sold for the entire year of 2018 and up till March 2019.

So we are looking at 26 CD failures out of 188,116. This is a 0.014% failure rate or 1 failure out of 7,235 units. Again, my assumption may not be correct, those that are concerned can chime in. This sounds rare, but I still worried for my 2019 CX-5 Touring.
 
MyFirstMazda said:
And from the NHTSA web site for my vin:

Jun 27,2019
Manufacturer Recall Number3719F
NHTSA Recall Number19V-497
Recall StatusRecall Incomplete, remedy not yet available

Summary
On certain subject vehicles, the powertrain control module (PCM) software controlling the hydraulic valve clearance adjuster may operate improperly when transitioning from cylinder deactivation to full cylinder activation modes while driving, due to inappropriate control logic of the PCM. As a result, an intake valve rocker arm may come out of position and make contact with internal engine parts, which may cause an engine misfire and loss of power and/or Malfunction Indicator Light (MIL) illumination.

Safety Risk
In the worst case, engine damage may occur, resulting in engine stall while driving without ability to be restarted, which may increase the risk of a crash.

Remedy
A Mazda dealer will reprogram the PCM with improved hydraulic valve adjustment control software, so that it may operate properly when transitioning from cylinder deactivation to full cylinder activation modes while driving.
Click to expand...

So what exactly "Recall Status - Incomplete: Remedy not yet available" mean?
It sounds like "Houston we have a problem, but we do not have a solution yet"
Sounds like we have to monitor for an update as to when they have the SW to reprogram the PCM, then we can take the car in.
 
yrwei52 said:
No, based on those reports by people who have had the fallen rocker arm, they hardly felt much performance difference until the engine fell into the limp mode. That's the danger of this problem. No codes were generated after the PCM update with fallen rocker arm either which makes me believe the PCM update actually masks some codes too.

Further, replacing the entire engine definitely is a lot more expensive and complicated than simply put the fallen rocker arm back to the position. The mechanic at the dealer has open the valve cover checking the falling rocker arm, it's a piece of cake to put the fallen rock arm back once he/she spotted the rocker arm has fallen.
Click to expand...

Can you test out the car to determine whether the rocker arm is still in place by pushing the car to 70-80 mph? or pretending to pass someone on the freeway? If you push the car and it responds normally, then you don't have a dislodged rocker arm.
 
Hi, new member who bought a new 2018 GT CX5 in Sept 2018 here. I just checked several sources for recalls on my VIN. MyMazda and NHTSA both say I have 1 open recall (3719F) My free account at MyCarfax shows I have two open recalls (3719F and 3619F). The second one is for undercover welding. There was a poster earlier here mentioning that he saw two recalls for his CX5 one day, and then only one recall the next day. Now I'm paranoid about whether my VIN was tagged accidentally as having this additional issue, or if the recall was accidentally removed and now I can't get it fixed... These recalls were the last thing I wanted to hear about for my new car :/
 
so far that is the big confusion everyone has.

1. mymazda lists 1 recall for thr CD rocker arm issues.
2. carfax lists 2 recalls. The first is for the cd issue, the second for the metal part welding issue.

so far its looks its not by vin ranges, but recalls show for all 2018+ years.
Even some cars on dealers lots show recalls if you check their vin.

p.s.
You cank check mazda recalls without the need to register at mymazda.
https://www.mazdarecallinfo.com
 
Tran7270 said:
CD failure rate:

The question we all want to know is how rare or widespread this CD related failure is.
I have been searching the internet to see if there are reports of Mazda CD failures associated with the 6 and the CX-5 from News outlets, but nothing came up beside forum discussions, this site included. So does this mean the problem is rare?

I came across a Consumer Report Used Cars magazine today and CR gave the 6 and the CX-5 both an "Excellent" (highest) rating for reliability across all categories including Engine Minor and Engine Major for model year 2018. So does this mean the problem is rare?

Let me crunch some sale figures relative to the number of reported failures to get an idea. To be clear, my assumption may not be correct, those that are concerned can chime in.

Go Hawks first reported the CD issue in his original post dated 5/3/19 and he said "For the year model 2018, Mazda added cylinder deactivation to the engines that are installed in both the CX-5 and the Mazda 6 models. Unfortunately this system is what caused the trouble for us and, at last count, at least 26 other customers that Mazda has confirmed"

Assumptions:
1. I don't know if 26 failures included both CX-5 and 6, but let's assume 26 are all CX-5 failures (worse case).
2. 26 failures are nationwide (I can't imagine this many failures reported at one dealership Go Hawks went to)
3. We know CD was introduced beginning model year 2018 and after and since Go Hawks OP was 5/3/19, I will use March 2019 as a cut-off date to calculate sales figures.

Sales figures for CX-5:
2018: 150,622 units sold (according to "Car and Driver")
Jan 2019: 10,652
Feb 2019: 13,377
Mar: 13,465
Total: 188,116 units sold for the entire year of 2018 and up till March 2019.

So we are looking at 26 CD failures out of 188,116. This is a 0.014% failure rate or 1 failure out of 7,235 units. Again, my assumption may not be correct, those that are concerned can chime in. This sounds rare, but I still worried for my 2019 CX-5 Touring.
Click to expand...
The rocker arm problem should be relative rare, as the cylinder deactivation itself should rarely happen based on its preset criteria.

But how often this problem happens is not the point. It's its unpredictable nature which is very dangerous like OP keeps emphasized. You'll never know when the rocker arm has fallen off, until at the time you need full power and found the engine falls into the limp mode! I hope Mazda has found out the real cause of the problem, and design a fall-safe hardware where even if the oil pressure varies out of the specified range, the rocker arm still would stay put. Remember oil pressure keeps changing during engine operation, and the use of different viscosity, temperature, and even the low oil level also contribute different oil pressure. Controlling oil pressure with software alone simply is not a feasible task, and the fact of this problem happening is the proof that the PCM software simply can't cover every situation on oil pressure changes.
 
shadonoz said:
Well done, OP, sticking to your guns and reading them the riot act.
Click to expand...

Pretty much brought this whole thing to light. This is still not being reported in any official capacity, nothing on any of the auto news sites.
 
Tran7270 said:
So what exactly "Recall Status - Incomplete: Remedy not yet available" mean?
It sounds like "Houston we have a problem, but we do not have a solution yet"
Sounds like we have to monitor for an update as to when they have the SW to reprogram the PCM, then we can take the car in.
Click to expand...
This's my question too, although the recall notice does have description on "Remedy" or "Repair".
 
Codeniko said:
Hi, new member who bought a new 2018 GT CX5 in Sept 2018 here. I just checked several sources for recalls on my VIN. MyMazda and NHTSA both say I have 1 open recall (3719F) My free account at MyCarfax shows I have two open recalls (3719F and 3619F). The second one is for undercover welding. There was a poster earlier here mentioning that he saw two recalls for his CX5 one day, and then only one recall the next day. Now I'm paranoid about whether my VIN was tagged accidentally as having this additional issue, or if the recall was accidentally removed and now I can't get it fixed... These recalls were the last thing I wanted to hear about for my new car :/
Click to expand...
Don't worry. I can imagine Mazda North American Operations are in chaos right now trying to handle these two recalls especially the rocker arm one. Mistakes will happen and we should wait for few days until things settled. I believe every 2018 and 2019 CX-5 with cylinder deactivation will get this rocker arm recall, and every 2018 and 2019 CX-5 will get undercover welding recall.
 
I called my dealer today to schedule an appointment. They said that they do not have the parts to do the recall fix and they will call me when they are prepared to do the work, and I can schedule an appointment when they contact me. Interestingly, when I said I had a recall, and they looked up my car, they asked me what the recall number was as if they didn't see a recall in their system. After I gave them the number they confirmed it was a rocker concern.
 
Last edited:
MyFirstMazda, what do you mean parts, the PCM reprogramming doesn't require parts? It only requires the reprogrammer, which the dealer should already have to use on all other cars.
 
yrwei52 said:
I hope Mazda has found out the real cause of the problem, and design a fall-safe hardware where even if the oil pressure varies out of the specified range, the rocker arm still would stay put. Remember oil pressure keeps changing during engine operation, and the use of different viscosity, temperature, and even the low oil level also contribute different oil pressure. Controlling oil pressure with software alone simply is not a feasible task, and the fact of this problem happening is the proof that the PCM software simply can't cover every situation on oil pressure changes.
Click to expand...

+1 Seems unreasonable that Mazda would not design the system with that in mind.

This should not be happening.
 
7eregrine said:
Pretty much brought this whole thing to light. This is still not being reported in any official capacity, nothing on any of the auto news sites.
Click to expand...

That may change now that a recall has been issued. Bad news for Mazda.
 
MyFirstMazda said:
I called my dealer today to schedule an appointment. They said that they do not have the parts to do the recall fix and they will call me when they are prepared to do the work, and I can schedule an appointment when they contact me. Interestingly, when I said I had a recall, and they looked up my car, they asked me what the recall number was as if they didn't see a recall in their system. After I gave them the number they confirmed it was a rocker concern.
Click to expand...

Right. Delay, deny, deflect. That won't work for long.
 
gdluke said:
MyFirstMazda, what do you mean parts, the PCM reprogramming doesn't require parts? It only requires the reprogrammer, which the dealer should already have to use on all other cars.
Click to expand...

My guess is they didn't hear about the recall and assumed that it required parts. They can't fix the car if they don't know about the details of the recall yet.
 
Tran7270 said:
Can you test out the car to determine whether the rocker arm is still in place by pushing the car to 70-80 mph? or pretending to pass someone on the freeway? If you push the car and it responds normally, then you don't have a dislodged rocker arm.
Click to expand...

The first person to have the the rocker displacement didn't know it was off. His car went into limp mode and he thought it was from hitting the red line. He brought it to the dealer, they reprogrammed the PCM and he drove it ever since without any symptoms. After Go Hawk discovered the real issue, he and others on this thread told him to have the dealer check the rockers. He did, after a lot of hassle and low and behold they found the rocker off. Then they replaced his motor.

This is his first post about the issue, was back in April.
https://www.mazdas247.com/forum/sho...e-at-Redline&p=6641913&highlight=#post6641913
 
Last edited:
Had exactly the same experience.
(Dealer had no clue, didnt have the parts. Needed my info to look it up and finally find it)
Will give them a call next week again
 
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