1990 Audi 90 Quattro Service and Repair Manual

This manual for the 1990 Audi 90 Quattro is built around the exact 20v Sedan trim and the 2.3L inline-five (engine code 7A) under its hood, so the torque values and procedures inside track what Audi actually published for this car rather than a generic 90-series writeup.

Engines covered

• 2.3L inline-five — DOHC, naturally aspirated, gasoline

Body styles covered

• 4-door sedan

Trims covered

• 20v

Known issues on the 1990 90 Quattro. Three recalls are on federal record for this model year. The first covers the transaxle: differential oil is lost over time to evaporation, and the resulting low fluid can wear the bearings and gears until the differential fails, in extreme cases locking the front wheels and causing sudden deceleration and loss of control. The second covers the front airbag sensor and control module, which can fall short of Audi's durability standards and inadvertently deploy the restraint system without warning, risking loss of vehicle control. The third covers the steering column lock: improperly manufactured lock bolts can break under force, leaving the steering wheel locked even after the ignition is turned. Owners have filed 6 complaints for the year. The factory diagnostic and repair procedures behind each of those systems are here.

From a differential fluid check to inspecting the airbag sensor wiring or the steering lock assembly, it keeps you on the OEM procedure and the correct specification for your specific 1990 90 Quattro.