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Mazda MPV: Problems & Solutions



  • tomj5tomj5 Posts: 209
    Yeah you are right. I checked my MPV with 4 seasons pack(big battery) and that is a crappy ground cable. It is way too small. The kids have bigger cables on their motorcycles... The cable runs from the battery to a car body (body ground) (not engine block) right below the battery. Where moisture and battery acid can get to the ground point. Another small cable runs from that point to an engine ground... That is the dumbest grounding system I have ever seen...
    The battery ground should run to the engine block close to the starter and another cable should run to the tranny frame and a third cable to the car body..
    My MPV runs good because of the dry desert where I live. Plus the big battery doesn't fume as much as a smaller one..... biomed_eng has hit on a very good possible solution..........
  • dan2004dan2004 Posts: 86
    Perhaps to use cables with alligator clips (in addition to stock setup) to test various grounding alternatives to see if they make a difference?
  • I tried to delete my "Post 3352" because I am in violation of forum rules by linking to other forums. It didn't delete for some reason.

    Back on subject...marketers call it HyperGrounding but in all reality it is merely fixing the poor grounding that Mazda provides.

    As any electrical engineer knows, "good" grounds are EXTREMELY important for low noise logic performance (i.e. computer controlled shifting), high current actuation (i.e. transmission solenoids), and reliability and consistency in design and performance.

    Ask your dealer if they have pursued this avenue.
  • 1. You can try the "before and after" method. My suggestion:
    a. hearty connection from the transmission to the chassis (at least 6 ga).
    b. hearty connection from the battery to the chassis (at least 4 ga).
    c. from the transmission ecu (location??) to the chassis (at least 10 ga).

    2. If you are an EE or tech and have an o-scpoe or digital voltage recorder, drive around and monitor the voltage between the above three suggestions one at a time and see which fluctuates or if there is any correlation between shiting moments and ground potential shifts or spikes/drops. Troubleshoot from your observations.

    Collect many happy smiles :) from MPV owners when you find the offending ground point or points.
  • Bought a 2003 MPV ES new in August. Took me a couple of weeks to realize the drivers side seat (leather) is highly uncomfortable. Feels like a couple of rocks under the right side of the seat bottom. If I sit a certain way it's not too bad. On a long trip I think I'd have to be hospitalized (ha). Has anyone else had this trouble? What are my chances getting this fixed under warranty. Due to go in any day now for 3k mi. check up.
  • My DW and I purchased our 03 LX in August. Since then, I have noticed hard shifting from 2nd to 3rd gears, but only when the traction control is engaged. This past weekend, our family went on a road trip and I experimented with the traction control feature--results: whenever the traction control was turned off, no hard shifting. I wonder if the software for the TC is causing some problems for the automatic transmission?


  • dan2004dan2004 Posts: 86
    Perhaps the best place to start is to check that all existing ground straps and connections are tight.
  • steverstever Posts: 52,572
    A bit more info is in the Grounding Kit discussion.

    Steve, Host
  • bottgersbottgers Posts: 2,030
    Personally, I could live with the hard shifting. It's not that big of an annoyance. The ONLY thing that worries me about it is what it's going to do to the tranny in the long run. I don't want to drive the van without the dealer being able to fix the problem, only to have the tranny scatter all over the road the day after my warranty expires. That's my only issue with the hard shifting tranny.
  • dtownfbdtownfb Posts: 2,918
    bottgers: I would take it in to the dealer to look at and get the stiuation documented. So if something were to happen to your tranny, at least it is on record.
  • I recently checked out the JATCO (Japanese Automatic Transmission Company)web site. Bottom of the home page had a small website email connection (really tiny). I'm composing a pointy email that would discuss the loss of honor these folks are being slammed with because Mazda is skirting the issue of the MPV tranny and making them look really bad. There may be more than one way to "skin a nippon". Any thoughts:
  • 2004 MPV purchased 12-23-03. First and most offensive hard shift at 154 miles. Several others since then happening between 2-3 shift and 2-3k rpm. At almost 500 miles dropped car for 2nd dealer evaluation today. En route to dealer no hard shifts. Noted that the temp was between 12-17 degrees F. Previous hard shifting happened when outdoor temps were warmer. Other members have similar observations?
  • If you read back on this thread a ways, you'll see that we all noticed the hard shift happens when the engine is at full operating temp. With the colder weather the engine probably takes much longer to get warm and may never reach a high enough temp to set off the hard shift problem. Although we experienced a couple of hard shifts with driving it right out of our garage a few weeks ago. So who knows, it's defective, we've stopped trying to analyze it.

    I would highly encourage everyone with this problem to at the very least demand an extended warranty on the power train at no cost and no deductible. We screamed and yelled enough and we got a bumper-to-bumper warranty on the car for 7 years/100K miles for free. Start with your dealership's GM and they will probably refer you to a regional Mazda rep who can make it happen. You still have the option to pursue the lemon law in the future even if you take the warranty.
  • user777user777 Posts: 3,341
    did you try to corroborate the observation made by another owner recently that turning off the Traction Control made the shift problem go away?

    your van is the one where you can reliably get the thing to hard-shift right?

    it would seem it would be good for someone else to attempt to either add or remove support for that observation.
  • Sure, I'll give it a try. My husband is handing the van over to me this weekend to be the primary driver of it from now on because it's making him a nervous wreck. He's not coordinated enough to avoid the hard shift, but I can get around it. I know, it's weird, the woman driver is more skilled than the man driver in our relationship! Must be all the mechanical engineers in my family. So I'll give it a try this weekend when I'm out and about.
  • dtownfbdtownfb Posts: 2,918
    So much for giving the wife the safe car. I wish I could get away with that in my house.
  • user777user777 Posts: 3,341
    too nervous to drive the thing...or maybe he's peeved (sorry) it's getting hammered on...

    was he the one who drove the purchase? i wouldn't be nervous if we had purchased one (and we had driven three), but it would erk me to no end each time i got behind the wheel...and THAT would make the rest of the people in the car nervous for sure.

    well...with all those MEs in your family - hope you design a good experiment.

    but seriously - if you notice the effect, you're going to have to bracket the observation (that the Trac off mitigates), by a few runs with the Trac on to make sure the mitigation isn't a function of the vehicle warming up.

    then as a control, get your husband to drive it in both configurations. ;)

    good luck.
  • bigdadibigdadi Posts: 72
    I have the MPV without the traction control, still having the hard-shift.

    The hard-shift happens when you hold on the pedal after moderate acceleration. If you keeps on pedal down or release the pedal a little before the 2-3 shift, you can get around it.
  • It's probably more irksome for him than makes him nervous. Every stinkin' time it does it he lets out a "sheesh" or a "grrrr", and then we get irritated. I finally told him if it bothers him so much I'll drive it and he said ok. He can't seem to figure out the right time to let up on the gas pedal to prevent the hard shift either. I can do it pretty well so I'm taking the car.
  • I have had my MPV in the shop since 11/18/03 and have been living with a service rental (compact, not a van). The shift in my van is so hard it lost traction once in the rain (I won't let my wife drive it, and certainly not with the kids in it). Don't know how it would do in snow because it's been in the shop since before we had snow up here. MN Lemon Law has three criteria for a getting your money back and mine has met all three. Coincidently enough, after I sent a certified letter to Mazada involking the Lemon Law, THEY NOW HAVE A FIX!!!! Magically, just after my letter, LUCKY ME!!! Actually it's better than that, Mazda at one point told me (months ago) they had a fix but the EPA had to approve it first. I opened a case (324123438) with the EPA who said they knew nothing about it. I don't want a fixed van, or a replacement van, or anything more to do with Mazda other than giving me my money back. They're liars and it's just a matter of time before someone gets in an accident as a result of this ongoing problem. Good luck to all of you.....get a lawyer, I am.
  • tccmn1tccmn1 Posts: 278
    I want to hear more about this fix. I've been on a LIST at a north metro Mazda dealer for 2 months waiting. I understand there is quite a list there too! If the FIX is here, how are we going to find out other than just calling the dealer...?
    I've had my MPV a year in late Feb. Again, I love this vehicle; handling, parking, etc. The tranny thing does not peeve me TOO much since I know they will stand behind it. Chrysler did/does the same with their crummy trannies. I had two such Chryslr. mini's with new tranny's put in at 90K by the this is nothing much new to me other than frustrating that I'm STILL DEALING WITH THIS ISSUE IN ANOTHER BRAND!
  • backybacky Twin CitiesPosts: 18,906
    I was in a presentation today by an expert in systems engineering, and as he was talking I thought of the hard shift problem. He talked about a particular automaker (which needs to be nameless due to confidentiality issues) about their quality problems in embedded systems (e.g. transmission control software). One example they discussed with him was that sometimes when a driver turns on the A/C and opens a power window at the same time, the trunk flies open (power release obviously). The interesting thing about this problem is that all three systems are separate, and when the automaker thoroughly tested each system they were all perfect. The speaker explained that the automaker was having a problem with the logical architecture of their embedded software components. The physical architecture for each component was fine. But the logical architecture, the interaction of the components, was flawed in some way. The simultaneous operation of the A/C and the opening of the window triggered some event that caused the trunk opening system to respond incorrectly.

    What does this have to do with hard shifts, and the difficulty in fixing them, you ask? Just this: what if the Jatco transmission and its software is actually not flawed at all? What if the problem lies in its interaction with other systems? For example, what if there is a problem in the interaction between the transmission system and the throttle-control system, such that certain inputs from the throttle-control system, under certain conditions, cause an inappropriate response from the transmission system? If this were the case, it could make the problem difficult for Mazda and Jatco to diagnose and fix. I'm not excusing the delay in getting a fix, but if this theory is correct it could help explain the delay.
  • Although they are separate systems...they use the same power and ground.

    I am sure if the trunk, AC and, power windows used independent power sources the "trunk pop" interaction would not occur (unless the problem is caused by radiated noise!)
  • backybacky Twin CitiesPosts: 18,906
    The trunk-pop problem was just an example of how systems can operate perfectly by themselves, but interact incorrectly. If you want to overanalyze that real-life example, be my guest. The point was that Mazda has been telling owners that there's no problem in the transmission, or that they haven't found it yet. I was just suggesting that maybe the problem isn't in the transmission and its software, but in how other systems interact with it.
  • steverstever Posts: 52,572
    Yeah, sometimes my brain and mouth are working perfectly, but together... forget it.

    Steve, Host
  • user777user777 Posts: 3,341
    well presented.

    one problem (from my perspective) is if there is an inherent design defect in the "logical architecture", then one wonders why all vehicles with identical architecture don't seem to exhibit the problem.

    to counter that - just an example or two:

    one might assume that if the system design is marginal and not very fault tolerant, a component of the architecture could be non-conforming...say perhaps a component on a commom communications bus sending messages when it shouldn't be resulting in message collisions between boxes/modules...and the result could be poor overall system behavior / performance.

    another possibility raised before in the thread is simply just one faulty sensor.

    these are evidently fairly complex systems and without a better understanding of the system design and operation, people may falsely conclude the defect lies in one area, when in fact it really lies elsewhere.

    so yes - i'm with you - perhaps the TCM and ECM or other pieces like the transmission aren't working together as they should.

    there have been some observations that when the vehicle is warm - the likelyhood of the hard-shift goes up. that might fit with a thermal sensitivity - a faulty transducer or a faulty micro-processor based component which is being affected by some heat source.

    if that were the case though, would the mitigation via software patch alone be sufficient?

    one wonders. it is an interesting problem, with i'm sure an interesting ultimate root cause...
  • Anyone want to discuss the hypergounding theory and engine temperature input at this point. Talk about interaction. All these folks that are bolting on hypergrounding setups are raving about how much better everything works on their cars once everything is properly grounded. And I haven't heard anyone complaining about cold engine 2-3 shift problems. So.....would a properly grounded tranny, engine, and TCM interact a little better? I heard from a few of you that ran out to look at their punny battery grounding cables. Perhaps saving a few pennies on weak wiring may cost have Mazda big bucks in the long run.
  • dan2004dan2004 Posts: 86
    For the past week I have stopped experiencing the hard shift problem on my 2004 MPV. It is too early to say if this is going to stick or only temporary, but I put on about 300 miles without experiencing one hard shift, which never happened before.

    These are some of the possible contributing factors:

    1) Shortly before this change I had the ATF replaced with Mobil 1 ATF, although the hard shifting continued right after the change

    2) I took the MPV on a week long ski trip which put 400 miles of high speed and up and down hill driving on the car. I started noticing some improvment while doing the hill driving.

    3) The MPV past the 3000 mile mark

    4) After reading the posts on the hypergrounding, I tightened the battery ground cable at the point where it is bolted to the car frame.

    I think there have been other posts noting improvement after extended highway runs.

    However there could be a zillion other factors, and the problem could return anytime.

    Good luck to all and will keep updating my situation. In the meantime I'm keeping my fingers crossed.
  • Good Luck, keep us posted.
  • vickie5vickie5 Posts: 12
    My 2003 MPV now has a 4900 miles on it. Yesterday on the way home I hit the button to close the sunroof, It slid forward and raised up to close, BUT didn't stop and kept on going. There was a terrible popping sound and it died. Nothing worked. I stopped by the dealer after much tinkering they have to replace the motor and the sensor....GREAT!! The tech asked if the car was still under warranty looked at the work order and said "OH you only have 4900 miles on this car." EXACTLY!!! While I was there I also had them re-check the tranny wanted it on record a second time. I made my way to the Service Manager to talk to him about the tranny slipping. The guy was a total arrogant jerk. Get this he told me that **most** cars have tranny problems and it shouldn't be a concern. WHAT!!!! I reminded him that this car is a NEW car and to please not even go there with me. Being that I am of the female persuasion I guess he thought I am an idiot and didn't know what I was talking about. I let him know different. Of course after the "test drive" I was told the tranny shifted like butter and since they couldn't duplicate it at the shop...then oh well. I'm really starting to get irritated with this whole thing. Since my first visit to the dealer on 11/26 I have kept a record of the tranny slipping and banging. When I go back to the dealer to get the sunroof repaired I will drop the NHTSA Complaints print out, the print out and the MPV Club Index on his desk regarding the phantom banging shifting problem that everyone is imagining. Could someone tell me how I can get in touch with the Mazda Western Regional Representative so I can work him and get the warranty extened. Any help would be appreciated. I'm so tired of getting the "I don't know what your talking about" look from the dealer. This is so bad. If this van was a dog I would have already put it to sleep! --Thanks
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