Description & Operation

WARNING: Vehicles are equipped with air bag supplemental restraint system. Before attempting any repairs involving steering column, instrument panel or related components, see SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM in appropriate AIR BAG RESTRAINT SYSTEMS article.

CAUTION: When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.

CAUTION: On vehicles equipped with Audi Telematics by OnStar, switch-off the emergency (back-up) battery for the Telematic/Telephone Control Module prior to disconnecting vehicle battery. Emergency battery is turn On and Off using VAG 1551 scan tool or VAS 5051 tester in diagnostic function CHANNEL 8 ADAPTATION 2.

S4 are equipped with power rack and pinon steering. Major components consist of steering rack (gear), hydraulic pump, serpentine drive belt, hoses and fluid cooler. Most power steering parts are not serviceable, if defective component is found determine cause via pressure and leak test. If there is a problem, replace suspect power steering component.