Using Diagnosis Check Wire

WARNING: This page is about a different car, the 2002 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.

To check for past codes, go to next step. To check for present codes, turn ignition switch to ON position. Wait about 20 seconds. Using Diagnosis Check Wire (09843-18040), connect terminals Tc and CG of Data Link Connector (DLC3). See Figure. DLC3 is located under left side of instrument panel. Go to step 3.
To check for past codes, connect Diagnosis Check Wire (09843-18040) to terminals Tc and CG of Data Link Connector (DLC3). See Figure. Turn ignition switch to ON position. Wait about 20 seconds. Go to next step.
If AIR BAG warning light flashes 2 times per second, system is normal (normal code). If AIR BAG warning light does not flash Diagnostic Trouble Codes (DTCs) or flashes DTCs without DLC3 connection, see DTCS NOT DISPLAYED or DTCS CONTINUOUSLY DISPLAYED under DIAGNOSTIC TESTS. If AIR BAG warning light is on continuously and DTC is normal (flashes 2 times per second), source voltage is low. Go to SOURCE VOLTAGE DROP under DIAGNOSTIC TESTS.
If AIR BAG warning light flashes, count number of flashes to determine DTCs that are set. For example, DTC 12 is: FLASH, 1.5-second pause, FLASH, FLASH. If more than one DTC is retrieved, a 2.5-second pause will occur between each DTC. Lowest numbered DTC will be retrieved first, followed by next higher number DTC until all DTCs have been retrieved.
After all DTCs are retrieved, a 4-second pause will occur, and DTC display will be repeated. See appropriate DTC under DIAGNOSTIC TESTS . After repairing, clear DTCs. See CLEARING CODES .
NOTE: If DTCs other than those listed under DIAGNOSTIC TESTS are retrieved, replace the air bag sensor assembly. If the AIR BAG warning light does not function as described, proceed to appropriate test under DIAGNOSTIC TESTS .