Get dealer to VIN-dicate problem with downshifting

  • Article by: PAUL BRAND
  • Updated: September 28, 2013 - 5:08 PM

Q: My 2009 Hyundai Sonata has an ongoing shifting problem. When I am slowing and the speedometer is crossing the 20-mile-per-hour mark, it “surges” as though I can feel the downshift. First we tried a transmission fluid flush, but that did not help. A second mechanic said it is just the way the car is and there is nothing functionally wrong. What do you think?

A: I’m not sure the transmission is the issue. Sensing or feeling a “surge” as the transmission downshifts might indicate an electronic control issue with the ECM (engine control module) and/or TCM (transmission control module). My ALLDATA automotive database pulled up several Hyundai service bulletins addressing shift quality issues. TSB #11-AT-003 addresses deceleration downshifts and TSB #12-AT-023 identifies an “improperly functioning transmission oil temperature sensor” that might affect shift quality and generate DTC fault codes D0711/P0712/P0713.

Hyundai has issued several programming updates for the ECM and TCM to address these issues. I’d suggest having your dealer check the VIN of your car to see if any of these updates have been done. If not, a scan tool might pull up specific DTC fault codes and the updated programming may smooth out the downshifts.

 

Q: I have a 1999 Mercury Grand Marquis 4.6-liter with 135,000 miles. It has a Gold Diehard battery that is about a year and a half old. On cold starts, no problems, but if I drive several miles and then turn the car off for a few minutes to an hour, when I start it the battery light comes on. After a few miles or a few minutes, it goes off. The battery and alternator test fine with my multimeter, but I can’t re-create the “light on” scenario in the garage while testing. It just comes on at start-up and then goes off.

 

A: By definition, the battery warning light illuminates when system voltage does not increase above battery voltage, indicating that the charging system isn’t recharging the battery. When the engine is started, the alternator’s “field” circuit must be electrically energized with battery voltage to create the magnetic field necessary to generate current.

On a restart where the “batt” light stays illuminated, try leaving the car in park and gently raising the engine rpm to 2,000 or so. If the warning light goes off, it means the voltage regulator built into the alternator has recognized the need to charge the battery.

With the key on but the engine not running, check fuse 3 (5-amp) and the “gen” fuse (10-amp) in the power distribution block to make sure they’re clean with solid connections, and check for battery voltage at the “F” (field) terminal on the back of the alternator.

Keep an eye out for a good deal on an alternator; you might need a new one in the near future.

 

Q: I own a 2005 9-2 Saab. It is due for new brake rotors. I understood there are four main types of replacement rotors on the market: flat (the usual OEM rotors), drilled, slotted and the combination of both. I’m looking to increase stopping power and reduce stopping distance while keeping the rotors from warping. Is there really a benefit to any these aftermarket rotors?

 

A: The different styles of rotors won’t really affect stopping “power” or distance. As long as the brakes have the “power” to lock the wheels and tires, it’s the tires that influence stopping distance the most. Better stopping power would require larger brakes and higher-grip tires. Look at it this way: Brakes are engines that work in reverse, so to speak. Brakes convert the energy of motion into heat. The bigger the brake, the more efficient the engine.

Slotted, drilled and vented rotors do offer one major advantage — they dissipate heat better, thus allowing more frequent and harder braking without overheating/fading/warping in high-performance and racing applications.

In your case, higher-performance brake pads would have a greater influence on stopping power than different style rotors.

  • get related content delivered to your inbox

  • manage my email subscriptions

ADVERTISEMENT

Miami - LP: M. Dunn 1 FINAL
Atlanta - WP: D. Carpenter 3
Arizona - WP: T. Cahill 7 FINAL
Chicago Cubs - LP: P. Strop 5
San Francisco - WP: J. Machi 12 FINAL
Colorado - LP: C. Bettis 10
Texas - WP: M. Perez 3 FINAL
Oakland - LP: S. Gray 0
Houston - LP: J. Fields 3 FINAL
Seattle - WP: F. Rodney 5
Cincinnati - WP: A. Simon 5 FINAL
Pittsburgh - LP: C. Morton 2
LA Angels - LP: E. Frieri 4 FINAL
Washington - WP: D. Storen 5
Kansas City - LP: K. Herrera 3 FINAL
Cleveland - WP: B. Shaw 5
Baltimore - WP: C. Tillman 10 FINAL
Toronto - LP: T. Redmond 8
Chicago WSox - WP: A. Rienzo 6 FINAL
Detroit - LP: E. Reed 4
St. Louis - LP: M. Wacha 2 FINAL
NY Mets - WP: J. Niese 3
Minnesota 4 Bottom 9th Inning
Tampa Bay 4
NY Yankees - LP: M. Pineda 1 FINAL
Boston - WP: J. Lackey 5
San Diego - LP: T. Ross 2 FINAL
Milwaukee - WP: K. Lohse 5
Philadelphia 0 Bottom 3rd Inning
Los Angeles 1
Charlotte 97 FINAL
Miami 101
Dallas 113 FINAL
San Antonio 92
Portland 53 3rd Qtr
Houston 53
Pittsburgh 3 FINAL(OT)
Columbus 4
Anaheim 2 3rd Prd
Dallas 4
St. Louis 0 2nd Prd 11:31
Chicago 0
Houston 0 FINAL
Red Bull New York 4
Connect with twitterConnect with facebookConnect with Google+Connect with PinterestConnect with PinterestConnect with RssfeedConnect with email newsletters

ADVERTISEMENT

ADVERTISEMENT

ADVERTISEMENT

 
Close