General Motors Corp.
The driver of a 1999-2001 Buick Century or Regal or 2000-01 Chevrolet Impala or Monte Carlo may comment that a ``Low Tire Pressure'' message or warning light intermittently illuminates on the dash, even though all the tire pressures on the vehicle are within specification.
General Motors said it is aware of the problem and reports that it usually surfaces when the vehicle is driven over rough, washboard-type road surfaces. An electrical glitch in the Electronic Brake Traction Control Module (EBTCM) is most likely responsible for the bogus warning lamps. New-design, upgraded modules are now available to eliminate the problem.
To determine if the vehicle you're working on can benefit from the new hardware, locate the part number of the existing EBTCM module. You'll find it on the lower/left portion of the label affixed to the module. Once you have the number, see if you can find it in the chart shown at left. If you can't, look for other problems in the Tire Pressure Monitor System. If the part number of the existing module is in the chart, replace the module with the upgraded unit listed.
Toyota Motor Sales
Toyota reports some 1994 Corollas are prone to producing a groaning or squeaking sound from the rear suspension over rough roads.
Worn stabilizer bar bushings are the likely cause. Upgraded bushings are now available to address the noise issue. Order part # 48818-12150 for Japanese-built models; part # 48818-02021 for U.S.-built models.
For a trouble-free installation, Toyota recommends removing the rear strut rods and applying lithium-based grease to the outer bushing ends.
Drivers of 1997-2002 Ram pickup trucks equipped with Hydroboost brake systems may come into your shop complaining of an annoying hiss-type sound from the power steering system.
According to DaimlerChrysler, one likely cause is restricted fluid flow between the pump and Hydroboost unit, or between the Hydroboost unit and steering gear. Installing new-design, higher-flow hoses between the pump and Hydroboost unit (part # 05086529AA) and between the Hydroboost unit and steering gear (part # 05086532AA) should alleviate the condition.
After installation, use tie straps to secure the new hoses to prevent chafing. To complete the fix, top off the power steering reservoir, start the engine, then turn the steering wheel lock-to-lock several times until all air is purged from the steering system.
Owners of 1998-99 626 models built before VIN 1YVGF22C*X5875297 may complain of an irritating squeal from the rear brakes.
According to Mazda, the noise usually occurs during the last 20 to 30 feet of braking with the brakes fully warmed, and is due to incompatibility between the brake shoe linings and drums.
Installing new-design rear brake shoes with improved friction material, part # GAYA 26 38ZB, should put an end to the squealing complaint immediately.
``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]
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Part No.'s of Existing EBTCM: Part No. of Upgraded EBTCM
9354019, 9370039, 9385240,9392260, 16265381: 12214535
9354029, 9370049, 9385250,9392270, 16265401: 12214534
9354039, 9370069, 9372000,9376289, 9385270, 9392290, 16265291: 12214532
9356769, 9361029, 9370059,9385260, 9392280: 12214533
9371984, 9376439, 9384629,12200399: 12214529
9376449, 9378240, 9384619,12200359: 12214531
9382019, 12200369: 12214530