Using Jumper Wire

Turn ignition on. Turn cruise main switch on. If CRUISE indicator light illuminates, leave ignition on and go to next step. If CRUISE indicator light does not illuminate, check CRUISE indicator light circuit. See appropriate INSTRUMENT PANELS article.
To retrieve DTCs, turn cruise main switch off. Ensure ignition is on. On LS400, connect Jumper Wire (09843-18020) between terminals Tc and E1 of Data Link Connector 1 (DLC1) located on top left side of engine. See Fig 1. On SC300 and SC400, connect Jumper Wire (09843-18020) between terminals Tc and E1 of Data Link Connector 2 (DLC2) located in left side of engine compartment. See Fig 2. On GS300 and GS400, connect Jumper Wire (09843-18020) between terminals Tc and E1 of Data Link Connector 1 (DLC1) located in engine compartment, forward of left strut tower. See Fig 1.
On all models, observe CRUISE indicator light for DTC display and check as follows:
- CRUISE Indicator Light Does Not Illuminate
  
  See appropriate INSTRUMENT PANELS article.
- CRUISE Indicator Light Flashes Steadily
  
  No DTCs set ("normal" DTC).
- CRUISE Indicator Light Flashes DTCs
  
  See DIAGNOSTIC TROUBLE CODE (DTC) DEFINITION table. Go to appropriate DTC under DIAGNOSTIC TESTS .
After checking for DTCs, disconnect jumper wire and turn ignition off.

Fig 1: Identifying Data Link Connector 1 (DLC1) Terminals (GS300, GS400 & LS400)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Identifying Data Link Connector 2 (DLC2) Terminals (SC300 & SC400)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DIAGNOSTIC TROUBLE CODE (DTC) DEFINITION

DTC ⁽¹⁾

Definition

Vehicle Speed Sensor Circuit

Stoplight Switch Circuit

Input Signal Circuit

⁽¹⁾	"P" codes with 4-digit numbers are read using scan tool. 2-digit codes are read using CRUISE indicator light flashes.