Smart Access System (Keyless Start) (Diagnostic Codes & Symptom Tests): Other Lexus GS III facelift

PROCEDURE

1. CHECK FOR DTC Delete the DTC. Check for DTCs again. OK No DTC is output. NG --> REPLACE POWER SOURCE CONTROL ECU OK --> END

1. CHECK FOR DTC Delete the DTCs. HINT: After all DTCs are cleared, check if the trouble occurs again 5 seconds after the engine switch is turned on (IG). Check for DTCs again. OK No DTC is output. NG --> GO TO DTC CHART OK: Go to next step
2. CHECK BASIC FUNCTION When the key is inside the vehicle and the shift lever position is in P, check that depressing the brake pedal causes the engine switch indicator to illuminate green. Result Result Proceed to Indicator illuminates green A Engine switch indicator circuit is normal but indicator does not illuminate green B Room oscillator recognizes key but indicator does not illuminate green C C --> GO TO ENGINE SWITCH INDICATOR CIRCUIT B --> GO TO ROOM OSCILLATOR DOES NOT RECOGNIZE KEY A --> REPLACE POWER SOURCE CONTROL ECU

Scheme 117

1. ENGINE START SYSTEM OPERATION If the engine switch is pressed with the shift lever in P or N and the brake pedal depressed, the power source control ECU determines that it is an engine start request. The certification ECU and other ECUs perform key verification via the LIN communication line. The power source control ECU activates the ACC relay. The power source control ECU activates the IG1, IG2, and ST CUT relays. The engine switch indicator light illuminates green. The certification ECU outputs a steering UNLOCK signal. The signal is sent to the steering lock ECU via the power source control ECU. The power source control ECU sends an engine start request signal to the ECM. The ECM and power source control ECU activate the ST relay. The ECM sends an ACC relay cut signal to the power source control ECU. The power source control ECU deactivates the ACC relay until the ECU detects an engine start request. When engine revolution speed reaches 800 rpm, the power source control ECU determines that the engine has been started. The ECU reactivates the ACC relay and turns off the engine switch indicator light. Symbols of power source control ECU Signals STP Stop light switch ON signal SSW1/SSW2 Engine switch ON signal ACCD ACC relay operation signal IG2D IG2 relay operation signal STR2 ST relay operation signal STR1 Park/neutral position switch signal TACH Engine start detection signal STSW Starter activation request signal CTSW Start assist signal