Description & Operation
Vehicles are equipped with power tilt and telescoping steering columns. Adjustment is made by moving tilt and telescopic manual switch located on left side of steering column. Selected movement signal is sent to tilt and telescopic Electronic Control Unit (ECU). Tilt and telescopic ECU sends signal to either tilt or telescopic motors to adjust to selected position. A memory feature incorporates driver's seat, outside mirrors and tilt and telescoping steering column positions. Information is transferred by multiplex control system. See MULTIPLEX CONTROL SYSTEMS - LS400 article.
Power tilt steering column also contains an automatic feature for easier vehicle exits. When key is removed from ignition, tilt and telescopic ECU will adjust column tilt fully upward and telescope fully retracted. When key is installed in ignition, steering column will return to previous tilt and telescopic settings.
If tilt and telescopic ECU detects a malfunction, ECU stores a Diagnostic Trouble Code (DTC) in memory. DTCs may be accessed using LEXUS scan tool connected to Data Link Connector 3 (DLC3), and active tests performed.
The power tilt steering column system consists of a key unlock warning switch, a manual switch, telescopic motor with position sensor, tilt motor with position sensor and a tilt and telescopic ECU. See Fig 1.