2007 Elantra GLS A/T (DOM 11/06)

OK, so new speedometer issue. I was driving to Atlanta this morning on I-85, and I had the cruise set at 80 mph. All of a sudden, the speedometer needle starts bouncing crazily and the cruise disengages. I'm able to continue driving (use the tach to guesstimate my speed) and the speedometer eventually returns to normal (after a period of about 20 minutes during which the needle would be bouncing all over the place for 5-20 seconds and then return to normal). I eventually had enough courage to re-engage cruise and didn't have another problem.

This same thing happened to me coming home from work about a week ago. Again, cruise was set at about 65, and the speedometer just went nuts and cruise disengaged. However, it only did it one time and then returned to normal for the remainder of my commute.

Any ideas? Another S/W bug? Anybody else experience this? I'd like to have some more info when I take it in to the dealership...

Chris

Hi Chris,
I think it might be a problem with the speed sensor. I had this problem happen to me when I drove an Impreza WRX. The sensor, which is mounted on the transmission box shorted out and my meter was jumping all over the place until it finally died.

As your car is still new, just take it to the dealership and have it checked out.


Daniel

That's what I thought it might be, because the speed settings with the radio were malfunctioning as well. So I figured it wasn't just a dash instrument issue. Thanks!

Chris

UPDATE: the dealer has had the car for several days now. They are still trying to finalize the troubleshooting stage, but they feel that it is more than a speed sensor. They are thinking that the ECU is going out. So I finally got a loaner Sonata Ltd on Friday. It's really nice; if I had banked for the Elantra Limited, I would be one happy puppy!

Chris

FINAL UPDATE: After having the car for 5 days and talking with Hyundai Technical Support, the dealership could not reproduce the problem and could not pull a trouble code that would tell them what's going on. So I went and picked the car back up. I'll just have to see if it happens again and see if I can gather any more data for the service techs.

FWIW, one of the techs said that the ABS module, ECM, and TCM all talk to each other, and occasionally one of them will get bad data and spit it back. He wasn't one of the guys who looked at the car, but he said it sounded like a microprocessor at the speedometer was causing the issue. So we'll just wait and see.

BTW, I had a 2008 Sonata Limited V6 as a loaner car for several days. I really loved all of the "extras", but the car was SO much heavier than the Elantra. I guess the perfect balance would be to get an Elantra Limited. But I was really glad to get back in my Elantra. I also found out (from tech mentioned above) that I can't just add the trip computer option to my GLS. Apparenlty the GLS and Limited have different wiring harnesses, different gauge clusters, etc. It's not just a simple software upgrade like I thought. So I'll have to forget about it or look at an aftermarket solution (anybody got any ideas?) or trade up to a Elantra Limited (or maybe an Elantra GT/Wagon Limited!).

Chris

This post has been edited by fastmov4: Apr 23 2008, 03:53 PM

I am very happy and fortunate to have found a '07 Elantra Limited where I live and at a great price. The "Limited" models seem to be very rare in Michigan!

*NEW UPDATE*

My wife reported that the speedometer activity happened to her, as well, on a recent trip to Atlanta. Apparently, though, it didn't do it the entire trip. I haven't noticed it doing anything since I've had the car back. I thought maybe all the tinkering they did on it at the dealer might have "accidentally" fixed it, but no dice.

Chris