Owners of 2003-07 Cadillac CTS and CTS-V cars, as well as 2004-06 SRX sport/utes, may complain that the air conditioning control head flickers, then returns to normal operation. According to Cadillac, the flickering is usually intermittent, more noticeable at night and is caused by software issues in the control head module. Reprogramming the module with updated software is the only reliable fix. Check with a dealer for the specifics of the flash.
Volvo said that all of its 1999-2004 models can produce a knocking or clicking sound from the front of the vehicle. According to the carmaker, the noise is most obvious at slow speeds while turning, and with the body undergoing some sort of flexing or twisting motion (such as when entering a parking lot or going over a speed bump). A likely cause for the noise is the front bumper contacting the chassis side rails. The contact can occur on one or both sides of the vehicle.
To make a definitive diagnosis, raise the vehicle on a lift and check over the steering and suspension components. If everything looks okay, remove the bumper cover and look for contact between the bumper beam and chassis. If you notice rubbing marks, use a long pry bar to carefully pull the bumper away from the side rails. Once there's sufficient clearance, dab the scraped metal with anti-corrosion compound, reinstall the bumper cover, lower the vehicle and perform a road test to verify that the noise has been eliminated.
Some 2005-08 Tribute SUVs with automatic transmissions built from Aug. 1, 2004, through Feb. 15, 2007, may stall when coming to a stop or when shifted from Park to Drive or Park to Reverse.
Mazda says the problem can be intermittent, and usually occurs after an extended drive. Furthermore, the Check Engine light probably won't come on when the stall occurs and no trouble codes will be stored in PCM memory. A torque converter that's stuck in the lock-up mode is the likely cause of the condition.
To make a definitive diagnosis, connect your scan tool, look at the data stream and pay attention to PID TC_SLIPACT as the stall occurs. If the slip in the transmission is greater than 20 rpm in Drive or Reverse, you're dealing with an engine problem. If the slip is less than 20 rpm, however, the converter clutch is locked. Replacing the torque converter with an improved unit, part No. ZZCA-19-100, should eliminate the stalling concern.
"Factory Fixes" is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at [email protected]