NC MK3.5 2010 Powershift Auto
London based.
Advice on Sportshift Fault - faultfinding process or garage services near me.
Hi everyone,
I need help with my partners car (I’m more into maintaining vintage vehicle so totally out of my depth) .
Searched the forum and will again - once I’m fully over my latest bout of covid - ho hum.
My partners car is normally super reliable but last night the transmission started to behave very weirdly and became progressively unpredictable over about 30 mins, being almost undrivable as ended up mostly stuck in first gear, then would be ok for a while, then back on the fritz. We limped back home. I’ll give a short run in a while to see if things have improved (magically!).
Being a bit “old school” I first thought maybe the trans fluid might be low - yep thats the limit of my reach on this subject. Maybe its electronic?
2 videos below are of the dashboard whilst driving with the problem. You can hear the engine (which is fine) and moving the gearstick left/right from D to M to D mode as we try to get the transmission to behave, only for it to switch back to M mode after a few seconds.
Any help on how to go about fault finding and fixing is most welcome, or leads on local garages who know their stuff, else is main dealer my only option?
Yeah she’s not well
I’m thinking low fluid or gearbox filter change if it has one ?
I’ve a Merc diesel auto, behaves the same way when in need of oil change, especially when cold.
Clunking into first gear generally and then refusing point blank to change up or exceed 40mph if already on the move.
Hopefully you’ll get some advice on forum if indeed electronic gremlin.
I’m thinking and worth checking, leaking grommets?
There’s a fuse in the A pillar fuse board protecting the instrument cluster electrics, I’m just wondering if water has got in there.
It seems more likely such a problem has only just occurred, I guess auto gearbox problems get progressively worse.
Anyways always worth checking if that fuse board/carpets are wet in the passenger footwell, we have had a very wet last couple of weeks.
Not had an auto mx5 but fluid and filter changes on previous autos normally cured shunting, hanging or shifting issues. Some cars also required a tcm reset as well so it could relearn shift points etc. Not sure how sophisticated the mx5 auto box is but a simple disconnect and reconnect of the battery may be worth a try and see if it settles out also. I could be talking rubbish with this particular car, but it has worked in the past for me on others .
This makes sense to me. I’m going out on the street to dig about in the car to find that fuseboxe and check for damp. I’d appreciate any help on eactly where to look, what interior fittings to take apart to find it etc… Any diagrams or ldiots guide online you could suggest would be most welcome. thanks again.
EDIT - Do you mean the standard fuse box, the easily accessible one for regular fuses?
I checked the wiring, sound insulation, under crapets etc… and esp around fuse no7 (engine controls). Itss dry as a bone under there, nothing out of place (to my totally inexerienced eye). (the weird looking fuse adapter is for dashcam, nothing untoward).
I’ve saw somewhere there might be a auto transmission control box in the interior somewhere so might check for damp around there - when it stops raining and I can work out where it might be.
Any other suggestions are most welcome. thanks again for taking the time to help me along.
Water coming through the so called scuttle grommets (do a search) can cause all sorts of electrical gremlins. The water can get into various connectors in that area. The fault might cure itself if any water ingress dries out.
If you haven’t done so in the past, I’d get them sealed then see what happens. These auto boxes are very reliable.
Valid point mate, a Google search will hopefully find a gearbox reset post.
My Merc resets by , accelerator flat to floor, ignition on for 30 seconds , ignition off, hold accelerator down for 2 mins, release pedal.
Box then resets and learns driving style.
I’ve resealed the Scuttle Grommets, which def. needed doing. There’s no sign of damp on either foootwell. I disconnected and visually inspected the 2 block connectors on (what i think is) the Powertrain Control Module. They and the PCM seem dry. I also disconnected and reconnected the battery in case that reset the PCM (disconnected/reconnect the 2 blocks on it.). The weird shifting fault (as per the videos above) recoccured after driving about for 30-40 minutes, occuring 1-2 times ever minute so limped the car home.
I’m reading through the Miata.net forums too now. I’m thinking it migth be worth getting used PCM unit to try out so any leads on sourcing one would be most grateful (scrapyards of course).
The battery hasn;t been changed in about 5 year of ownershi and looks pretty old. Could it be a low voltage issue? Even with the engine running?
Any suggestions on the next checks?
I’d already be visitng a main dealer excep the nearest is about 15 miles away and getting the car there will be tricky…
Do you have access to an OBD reader, to scan the car for fault codes? This might provide a bit of prior knowledge, ahead of any dealer visit.
You could also have a look for any nearby transmission/gearbox specialists in your area. Unfortunately I don’t know much about the Powershift transmission, to know how it works from a design point of view. But does seem strange overall, for something that’s done less than 50k miles.
It could also be selector related of course, depending on how the shifter senses what gear has been selected. Especially if it’s going into manual mode of its own accord, ascertain whether that being caused by the transmission mis-interpreting what gear is being asked for (via mis-information from the physical selector or from the transmission control module), or whether it’s an issue with the transmission itself.
UPDATE: Sealing the Scuttle Grommets seemed to fix things. We’ve been running the car for a few days in wet weather, using aircon to dry out the interior. So far driven 20-30 miles without a problem. so hopefully that’s sorted.
Many thanks for all the advice, I really appreciate it. Goes without saying your suggestions saved me a whole load of grief and expense. Thanks again.
As per my previous post, I noticed the drivers side washer jet was not as powerful as the passenger side, a dribble in comparison, so decided to investigate this issue and remove the wipers and panel decking that obscures the flexible piping for the washers and remove the washer jets and clean them by blowing through with an air-line, fortunately, I have a small compressor, so this was called into use
Several attemps and blowing through the washer jets and pipework did not improve matters and as the jets are the type that produce a fan-type spray pattern and not a single water jet I decided to replace both Washer jets, as they also have a built in non-return valve, which was probably clogged with debris and causing the problem.
A quick look on MX5 Parts Website revealed that Genuine Mazda Washer Jets for a Mk3.5 were very reasonably priced and I also took the opportunity to purchase two new scuttle grommets (that are notorious for leaking and causing all sorts of electrical issues) and also two new blanking caps that cover the screw heads that secure the decking panels to the main vehicle bodywork, the the lugs often break off during removal so would be a problem when refitting. All this for only £20, an absolute bargain for the peace of mind it would give
The plastic deck panels were thoroughly cleaned and the new Washer Jet assemblies fitted. The bodywork area whre the scuttle grommets go was vacuumed out and I could see the thin rubber gasketst that seal both scuttle grommets to the bodywork were perished and the passenger side one was split, even before removal. By use of two screwdriver blades that had thin tips but were about 5mm to 6mm wide, thus they could easily be pushed under both sides to release the plastic barbs retaining the fitting of the old scuttle grommets and by gently twisting the blades the scuttle grommets simply popped out with out any damage to the paintwork, which was a result (see photo).
The whole area where the scuttle grommets go was thoruoughtly cleaed with a spirit based cleaner and once dry a good quality sealant was applied. I was fortunate, in that No2 son has a power boat and had recently been prepping it for this summers use, so there was a tube of marine grade clear sealant to hand. As per previous posts sealant was applied to the cleaned bodywork to form a complete ring around the scuttle grommet aperture and was left to partially cure for a while before refitting the newly purchased scuttle grommets, as this ensures a nice seal against the bodywork.
The pipework and nicely cleaned decking panels, as these are a lot easier to clean off the vehicle, were replaced and the system tested. A beautiful spray pattern is now produced at both washer jets when operated - result!
I also have the satisfaction that the scuttle grommmets have been replaced and sealed and should prevent any water ingress into the vehicle electrics
.
