Using Malfunction Indicator Light

WARNING: This page is about a different car, the 2002 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: DTCs are 2 digit numbers.

Turn the ignition switch ON.
Using the diagnosis check wire (SST 09843-18040), connect between terminals No. 11 (TC) and 3 (E1) of the data link connector No. 1 (DLC1). See CONNECTOR IDENTIFICATION .
Read the diagnostic trouble code from malfunction indicator lamp. If a diagnostic trouble code is not output, check the TC terminal circuit. The ECM controls the immobilizer function of this vehicle, DTC is output with engine data. As an example, the blinking patterns for codes; normal, 12 and 99 are shown in charts. See Fig 1.
When DTC 99 is output, there is a trouble of immobilizer. Start trouble shooting. See PROBLEM SYMPTOM INDEX table.
After completing the check, disconnect terminals No. 12 (TC) and 4 (CG) and turn off the display. In the event of 2 or more malfunction codes, indication will begin from the smaller numbered code and continue in order to the larger.

Fig 1: Identifying Indicator Light Normal & Malfunction Codes