Without Scan Tool

WARNING: This page is about a different car, the 2003 Lexus LS 430, 2002 Lexus LS 430, and 2001 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

Turn the ignition switch off.
Using special tool (09843-18040), jumper between terminals Tc and CG of (DLC3). See Figure.
Start engine with door open. Read DTC output by the flashing pattern of absorber control indicator light. For an example of normal code and codes 11 and 21 see Fig 1. In the event of 2 or more malfunction codes, indication will be from smaller numbered code to larger. For code definitions and testing procedures see DIAGNOSTIC TROUBLE CODE DEFINITIONS . .
If no code appears, inspect the Tc terminal circuit or absorber control indicator light circuit. See SYSTEM TESTS .

Fig 1: Identifying Blinking Patterns