2006 MT, ~6k miles.

About 6 months ago I was cruising along ~40mph, and DSC & TC & KEY lights came on and the TAC & MPH dropped to 0 all at the same time. Just for a second, then TAC & MPH back to normal, then a bit later to 0 again. Happened two or three times, and the engine was running fine, didn't sputter or miss a beat. After a while the DSC light went out, but the other lights stayed on until I reached my destination.

Over the past 6 months it has happened again 3-4 times. Seems to usually occur on the first start/drive after it has been sitting a while. The other day DSC & TC & KEY lights came on just a few minutes after starting and then 10 minutes later the TAC & MPH dropped to 0 4-5 times while crusing at 70mph. After I shut off the car and restarted it, everything seemed fine, and it didn't happen again for the rest of the day.

Any ideas?

 

Insight welcomed...

 

Unfortunately... sounds like either an issue with the PCM or the instrument cluster.
Are you still under warranty because this may be something a dealer should look at.

 

i have been having about the same problem, just starting up recently.

On monday when i took a hard left i had my ebrake, ABS,and traction control lights pop on, and stay on until i stopped and turned off the car, and started it back up. Could this be the same problem with the PCM or the instrument cluster?

 

Check your battery and make sure there is no corrosion on your battery terminals and make sure the battery cables are tight.

 

Main relay?

 

I think if it was a battery or main relay, he would also have trouble keeping the engine running.
But he quoted that the engine runs fine and doesn't sputter.

 

The battery would be unlikely..usually battery problems don't come and go that quickly...

The reason I said to check the relays is that I had one that failed like that...it was an almost instantaneous failure.....that only lasted for a sec...and then energized again and all was well for weeks at a time. If the car is moving it was difficult to notice the miss unless you were full on the gas when it happened.

This would be very unlikely...but worth a check

 

Thanks for the input. Still under warranty, so went ahead and had the dealer check it out. Of course it wouldn't do it for them, so they just printed out the codes and told me to bring it back when it did it again. They did run a self test on the gauge cluster and everything passed.

C1956 ABS/TCS
C2778 ABS/TCS
U1900 ABS/TCS/EPS/IC
U0073 EPS
U0100 RKE
U0073 PCM
U2516 SASM

 

Same thing happened to me but i was doing a hard right turn. it's happened twice.

Probably because i drop my car into first and uturn alot LOL

 

i had a similar issue and it was the negative terminal on the battery wasn't connected properly, happened just after i changed the battery. while driving the cluster would turn on and off and gauges all dropped etc.

 

When I crank up the car the tack will drop to zero then go back to normal when this happens the AT light flashes, engine light comes on, and dsc light as well. when I shut the car off and restart the dsc light is gone but the engine light is still there. I put my code reader on it and it reads U0100 most of the time and U0100 p/d . The booklet for the reader doesnt have that code. I searched online and it says "ecm/pcm lost communication" The car runs fine this is more of an annoyance to me.
Sorry to revive an old thread again but Im just currious to see if anyone has found out how to fix it.

 

U100 just means your scanner and PCM just didn't communicate that time. It does happen from time to time and I believe it has nothing to do with your overall issue.
However...........what scanner are you attempting to use? Have you ever used this scanner before.....successfully?


I know it won't be popular, but my experience with the issues stated in this thread are 85% of the time caused by weak interface..............corroded and/or dirty connections at the battery. It's plausible that it could be the alternator(or alternator connections) as well.

 

Yea Ive used it on my wifes toyota yaris when her maf sensor came loose. I thought the same thing too but when I do a reread it comes up with the same thing. I dont have this problem while driving the car just when starting up. I have a bully dog system that plugs into the obd2 and its not seeing any codes at all but its reading everything elses just fine. It doesnt happen all the time it averages once every day or so mostly when the humidity is high which makes me think that its just a bad connection getting moisture in it.
its an actron obd2 pocket scanner

 

If this just started happening in the last couple of days................and your battery terminals are clean and tight. Then take a trip to Autozone and have then do a loaded test on the alternator. FYI......I couldn't detect it with my multimeter. My CEL was getting set on start up and my scanner(system) wouldn't show any code at all even though I use it all the time, have seen many other codes(that I caused to check my system out) and mine is in the car and on all the time.

It's free, so go eliminate the alternator. Have them load test the battery as long as they are in there.
Make sure you come back and tell us how they checked out.
I had some very strange crap happening when my alternator started failing about a month ago. Some of the things in this thread sound eerily familiar, but not exactly the same.

 

its been happening about a month or so. I took it to autozone and used their code reader when it first happened and they cleared the code. It happened again the next day and I when and bought this code reader from them. Since then I have just been clearing the codes everytime it shows up. The only thing that I think that is odd about the car is that it has to turn over 3-4 times before it starts like an old V8 not like a normal newer car that you just bump it over and it starts. Im new to rotarys Im used to working on piston motors so I dont know if it is normal or not. the motor is new also.

 

Well, then we start asking some questions like...............what year is the car?
Reason..................04's and early 05's had a weak starter that has been upgraded and if an 04, you could check the number and see if you have old or new. This car does take a second or so longer than others to start-up. If you do a search you will see some videos with sound that you can compare good vs. bad and see. A couple of turns to catch isn't all that unusual.

Most important...................what the hell code is this that you keep clearing?
That's really, really, really important!
Need to quit clearing it and see what it is!

Also, is the scanner plugged in when you start the car or do you start it first and then plug the scanner in?

 

The scanner isnt plugged in at all when Im normaly running it I usualy have my bully dog monitor hooked up (Ive also tried not having that plugged in too but it makes no difference) when the code shows up I turn the car off completly and unplug the bully dog and plug in the scanner and turn the car on not starting the motor and read the code the code that is showing up is U0100 and every so often Ill get a second code that reads U0100 p/d when I clear it the codes goes away then engine light flashes I then rescan it and I show no codes and then I unhook the scanner then restart and engine light is off. The car is an 04 Auto trans. The dealership said it was normal for it to take a couple of turnovers bc its a rotary. I went to college to work on cars but this was before obd2 and we didnt cover rotarys guess Im a little out of date

 

Well finaly took my car to mazda cause the ignition coils failed which solved the hard to start problem. they said I was running off 3 coils then a second died then my car sounded like anyway they checked out the check engine light problem and said there was moisture getting on the ecm connector causing it to not read properly which I kinda figured that considering every time I washed it or it rained I got the code more frequently. Hope this helps anyone getting the same problem