1998 Buick Park Avenue Owner's Manual - Page 384

While parked, and with the parking brake set, try to turn the ignition key to LOCK In each shift lever position. @ Park on a fairly steep hill, with the vehicle facing downhill. Keeping your foot QII the regular brake, set the parking brake. @ The key should turn to LOCK only when ;he shift lever is in PARK (P). The key should come out only in LOCK. To check the parking brake's holding ability: With the engine running and tramaxle in NEUTRAL (N), slowiy remove foot pressure from the reginlag brake pedal. DQthis until the vehicle is held by the parking brake only. Q To check the PARK (PI mechanism's holding ability: With the engine running, shift to PARK (P). Then release ail brakes.