Hi, I'm getting used to my recently acquired 2009 GLS V6. I've very pleased with the car - it was purchased used with 12,100 miles on it and I'm close to 14,000 miles now. I've learned a few things about it so far, but one has me a little curious. In most every car I've owned manufactured in the last 15 years or so, the transmission programming is such that the engine is essentially decoupled from the drivetrain when you lift off the gas to coast down. This is for fuel economy reasons. In this car, it doesn't appear to do so until at a very slow speed. So, if I'm on the highway and I have gotten to, say 70 mph - as I lift off the gas I feel the enging slowing the car down. If I shift to neutral, then the tranny disengages and coasts better. I notice, however that somewhere between 20 and 30 mph, the drivetrain does disengage automatically. Odd that it does it a low speeds, but not higher speeds.

My fuel economy is quite good, so there are no problems. I'm just wondering if this is normal, however - or if there's one of the sensors in the tranny not telling the tranny to disengage when it shoud.

Do you other '09 V6 Sonatas feel that as well? Thanks!

This has been reported in Models going back to 06. The Torque Converter possibly? From time to time the Dealer might have you come in for adjustments.

There is a button on the left side of the dashboard - "ESC OFF". My car (Sonata 2007, V6) coasts better (not much better, but I can feel it) if I drive with "ESC OFF" light on the panel.

While not all Sonatas made for Canada sport ESC, turning it off is a terrible idea

Heh..... You must have never driven a Honda...... At least not an Accord.....

The torque converter locks up at ~45mph for economy. That eliminates the ~5% loss from slippage.

When you let off the gas, your torque converter probably remains locked until ~45mph.

Now,,, the locked torque converter will hurt your coasting gas mileage a little, but it's more than made up for
by getting better gas mileage while driving faster than 45mph.

Ideally, the TC would unlock at low or no throttle. Maybe your 09 is supposed to, maybe not. My 06 stays locked.

This post has been edited by bobad: Nov 2 2009, 02:55 PM

I like that characteristic about the Sonata. I've been driving manual transmissions for the past 25+ years and I appreciate getting some compression braking from the engine when I let off the gas. I don't think I could tolerate an auto transmission for too long otherwise.

Ive found a quick fix for the TQ converter lock up thing and engine braking.. Just when you are about to let off the accelerator hit the gas petal into the floor and let go (have to do this quickly) and it will unlock the converter and bring the rpm down to about 1k, this works great on the highway at speeds around 70-80 cause i dont get the slight jerk from letting on and off the gas...


I'd agree with that! Just the other day I was on a back road coming home from work, just me nobody else around, enjoying the music... and a deer decides its time to skip out in the middle of the raod as I'm doing 55, ESC came in really handy! I swerved around it, gotta dent on my fender from the **** thing, but without ESC and the Sonatas great brakes I probably would have went into some type of spin...

This post has been edited by Djonemore: Nov 3 2009, 01:06 AM

There are a ton of Deer in NJ. Similar to all the Alligators you see in Florida. Hit one of those which people do, and sometimes they win!

I drive this road almost every day for the last year and never seen a deer, this one came out of nowhere... Luckly for the ESC... If I had my Town Car, would have been a different story.