By on March 8, 2010


TTAC reader Tiburon Guy writes:

Hey Sajeev: Long time reader, first time e-mailer. I have a 2001 Hyundai Tiburon that I inherited from my wife when we got married (dowrys are making a comeback!). It has 70,000 original miles and I’ve maintained it properly. Recently a problem arose that the dealer could not point out nor could my personal mechanic (ASC Certified) determine the cause or solution to.

It’s an automatic transmission. Sometimes when starting the car, pushing the release button on the shifter is downright impossible. It’s stuck and won’t engage, which means I can’t shift into gear. After a few moments of wiggling and pushing and jerking (and crying on my wife’s part) it will give and we’ll be on our way.

This doesn’t happen all the time though, it’s once every month or so. Any idea what could cause this and if so, what can I do to fix or prevent it from occurring? We are the only owners of the car and have not raced or abused it. I’ve hunted the forums on the Hyundai fan sites and I can’t find anyone with the same issue.

Sajeev writes:

These brake-shift interlocks are a simple design: you push the brake pedal, the brake switch takes note, then a solenoid on the shifter releases it’s grip and you move out of park.  And a competent wrench should find the offending part rather quickly.

The brake switch is simple, check if the brake lights illuminate when you touch the pedal.  There’s probably a fuse, so the owner’s manual has you covered. Test the solenoid with a factory service manual (on-line or on paper) or pull it out of the shifter and stick 12v of juice at it. And removing the shifter might be a good way to check for binding in its mechanism. Let’s assume (hope?) this diagnostic tree was followed.

But if everything passed muster, perhaps the parking spot is the problem?  Many cars are harder to move from park with a transmission “loaded” by the forces of an uphill parking space. And sometimes the transmission makes a terrible sound when the shifter finally moves out of park.  The only solution is to engage the parking brake before going into park.  And reverse the operation when you return: start the car, put the autobox in neutral or in gear, and release the parking brake.

More to the point, I suspect you can Cliff’s Notes my writing, post it on a Hyundai enthusiast forum and get a straight answer in a matter of hours. That’s my ultimate recommendation.

Bonus! A Piston Slap Nugget of Wisdom:

There is significant mechanical waste in modern cars, items that neither improve the driving experience nor make the car any safer.  I suspect failed brake interlocks cause more stranded motorists, grey hairs, and unnecessary repairs than any potential lives saved from accidentally hitting the wrong foot pedal after start up.

Plus, the extra dollars added to a car’s MSRP are better spent on a fancy dinner with that special someone. And with that, I’d like to thank 60 Minutes for giving us this electrical pain in the ass, and make the obligatory hyperlink to Paul Niedermeyer’s excellent article on the Audi 5000.

(Send your queries to mehta@ttac.com)

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19 Comments on “Piston Slap: Beached Shark, Broken Diagnostic Tree?...”


  • avatar
    poltergeist

    I can’t speak for Hyundai, but the shift interlock circuit on current Honda’s isn’t as simple as described. The circuit runs through the PCM, which sends a command to the interlock solenoid. The PCM monitors brake pedal position and throttle position to determine if it’s “safe” to allow the trans out of park. A once a month failure will be exceedingly hard to track down.

    • 0 avatar

      Excellent point! Just about every modern car (in the last 5-10 years) has a body computer that processes a thousand functions. But the logic is still the same, there’s just a processor involved instead of a brake switch and a fuse.

      I’ve always wondered if disconnecting the solenoid at the shifter would work, not throw a warning light/body service code. Thoughts?

    • 0 avatar
      poltergeist

      Pretty sure (at least on Honda’s) that the solenoid is normally “relaxed”. It’s energized to allow the shifter out of park, so unplugging it will not work. Might not be that hard to remove the solenoid altogether once you get the console apart.

      On Honda’s the shift interlock is actually controlled by the engine management “PCM”. Still I doubt disabling the interlock would set a code….YMMV.

      I agree with gasser, find the manual release and use it, at least until it starts failing more often.

  • avatar
    jjolly2

    Wait a minute..There is a Hyundai fan site?

  • avatar
    gslippy

    You should upgrade to the 2011 Sonata.

  • avatar
    gasser

    Find the shift-interlock release button (owner’s manual), pop the plastic cover off it and use it when the shifter sticks.

  • avatar
    tced2

    My pet theory would be that there is some mechanical/lubrication issue at the solenoid. The solenoid is being activated at the correct time, but for mechanical reasons it cannot move to allow the shifter button to work.

  • avatar
    ClutchCarGo

    As an aside, assuming that Tiburon Guy was not a pedestrian before he wed, here is another illustration of a fundamental unfairness with cars and relationships: the guy is always going to wind up with the more problematic car. I worked with a guy who naively thought that he could buy a beater car for his girlfriend to drive to school. We all told him that he should shop carefully since he was going to wind up driving the beater himself while his girlfriend took over his nearly new car, and sure enough, within a month he was making excuses for being late to work because the beater let him down. Funny how that works.

    • 0 avatar
      Robstar

      This is one of the reasons my wife inherited our beater automatic and I bought a stick sports car. She couldn’t drive it if she wanted to!

    • 0 avatar
      educatordan

      I got off easy in my divorce. Wife ended up with the 1997 Escort Wagon with the rebuilt transmission, I ended up with the 2003 Ford F150. Two reasons – She couldn’t afford the payments (Escort was paid for) and she could afford the gas for the truck!

  • avatar
    Ken Magalnik

    Had that exact problem with the ex’s volvo, except that it would occur virtually every time she drove it, and almost never when I did. The (very hard to find) problem ended up being the ignition switch, over time, it developed a “detent” in between the run and start detents. After starting, I would (out of habit) return the key to “run”, where as she would let the spring action return it, and it would get stuck in between positions, locking the shift lever.

  • avatar
    stuart

    Our 2000 Odyssey had an interlock that I could never fathom. Wife had no problem; must’ve been me, personally. It seemed like it needed a brief delay after pressing the brake before it would unlock and allow the gearshift to move. Pulling the gearshift too early wedged the mechanism, precluding a shift; you must release the gearshift and brakes, and try again (stupid!). One day I caught it while it was dis-engaging, forced it, and broke something. Of course, the broken part promptly wedged in the gearshift, permanently locking out Park.

    I managed to get it home, pull the cover off the column, retrieve the broken piece, and it’s been great ever since! This is the best thing I ever broke on any car. I have no intention of fixing this, ever.

    stuart

  • avatar
    maxo

    Had this same issue with a 95 cutlass a while back (almost as awesome of a car as a tiburon…) intermittently, wasted my time playing with the parking on a hill theory but in the end there were two issues: one was that the brakelight circuit had a problem that had to be addressed by putting a new blinker unit thing in the steering column and maybe replacing some bulbs. Sorry I don’t really recall the exact parts, as I sold the hell out of that car many years ago. The 2nd was that in sun-baked interior temps some part of the solenoid and the connected levers appeared to be warped or something, when I hit the shifter button I could see it wiggle a bit but it wouldn’t manage to actually take down the interlock.

    I discovered 2 workarounds for dealing with it though: I learned how to crack open the center console in about 20 secs and manually pulled the lever connected to the solenoid to let it shift, but maybe this isn’t as easy in the hyundai. I just started to leave the pliers in my glovebox. I also eventually “fixed” my issue in a fit of rage by pulling HARD on the shifter until I snapped something, and from them on I no longer had to depress the brake pedal (or the shifter button) to change gears. probably wouldn’t recommend that fix though…

  • avatar
    guyincognito

    A vehicle I was working on had a severe “bitsy” problem right before launch. 10,000 vehicles were parked and ready to go to dealers when one of the drivers got in an could not get any of them out of park. It turned out that an adhesive in the brake shift solenoid body was melting in the hot August sun and flowing around the plunger, then setting overnight.

  • avatar
    Omoikane

    “After a few moments of wiggling and pushing and jerking (and crying on my wife’s part) it will give and we’ll be on our way.”

    Have you tried praying?…I heard it does wonders. If God can stop a Lexus with a stuck gas pedal, getting your transmission to shift should be piece of cake for Him :)

  • avatar
    Disaster

    This might not pretain to the 2001 models, but the 2003 Tiburon made the Consumer Reports “Least Reliable” list, with 161 problems per 100 vehicles. In comparison, the 2001 Toyota Echo only had 35 problems per vehicle.

  • avatar
    don1967

    Regarding Sajeev’s first remark about parking on slopes, I agree and further suggest angling the front wheel solidly into the curb until the vehicle virtually stops on its own. Then engage the parking brake, then shift into Park.

    Many vehicles – and almost certainly a 9-year old Tiburon – lack a sufficiently strong parking brake to prevent gear binding on slopes.


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