Smart Access System (Keyless Start) (Diagnostics - Introduction): Diagnosis Lexus GS III facelift

HOW TO PROCEED WITH TROUBLESHOOTING

HINT

1. Use these procedures to troubleshoot the push-button start function.
2. *: Use Techstream.

1. VEHICLE BROUGHT TO WORKSHOP NEXT: Go to next step
2. INSPECT BATTERY VOLTAGE Standard voltage 11 to 14 V If the voltage is below 11 V, recharge or replace the battery before proceeding. NEXT: Go to next step
3. INSPECT COMMUNICATION FUNCTION OF LARGE-SCALE MULTIPLEX COMMUNICATION SYSTEM (BEAN)* Use Techstream to check if the Multiplex Communication System (MPX) is functioning normally. RESULT Result Proceed To MPX DTC is not output A MPX DTC is output B B --> GO TO MULTIPLEX COMMUNICATION SYSTEM A: Go to next step
4. CHECK FOR DTC* Check for DTC and note any codes that are output. Delete DTC. Recheck DTC. RESULT Result Proceed to DTC does not reoccur A DTC reoccurs B B --> GO TO DIAGNOSTIC TROUBLE CODE CHART A: Go to next step
5. PROBLEM SYMPTOMS TABLE RESULT Result Proceed to Fault is not listed in problem symptoms table A Fault is listed in problem symptoms table B B --> Go to step 7 A: Go to next step
6. OVERALL ANALYSIS AND TROUBLESHOOTING* Terminals of ECU. Refer to «TERMINALS OF ECU»(ref-382772-S05456524992011012800000) DATA LIST/ACTIVE TEST. Refer to «DATA LIST / ACTIVE TEST»(ref-382772-S21316712222011012800000) NEXT: Go to next step
7. REPAIR OR REPLACE NEXT: Go to next step
8. CONFIRMATION TEST NEXT --> END

PROBLEM SYMPTOMS TABLE

HINT

1. Use the table below to help determine the case of the problem symptom. The potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
2. Inspect the fuses and relays related to the system before inspecting the suspected areas below.

PUSH-BUTTON START

Scheme 60

Scheme 61

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Scheme 64

Scheme 65

1. CHECK POWER SOURCE CONTROL ECU Disconnect the K73 ECU connector. Measure the voltage and resistance of the wire harness side connector. Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition AM1 (K73-33) - Body ground BE - Body ground +B power supply Always 10 to 14 V AM2 (K73-12) - Body ground BR - Body ground +B power supply Always 10 to 14 V SSW1 (K73-14) - Body ground P - Body ground Engine switch signal Engine switch pushed Below 1 ohms SSW1 (K73-14) - Body ground P - Body ground Engine switch signal Engine switch not pushed 10 kohms or higher SSW2 (K73-37) - Body ground B - Body ground Engine switch signal Engine switch pushed Below 1 ohms SSW2 (K73-37) - Body ground B - Body ground Engine switch signal Engine switch not pushed 10 kohms or higher GND2 (K73-6) - Body ground W-B - Body ground Ground Always Below 1 ohms LIN1 (K73-30) - Body ground W - Body ground LIN line Always 10 kohms or higher If the result is not as specified, there may be a malfunction on the wire harness side. Reconnect the K73 ECU connector. Measure the voltage of the connector. Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition ACCD (K73-11) - GND2 (K73-6) G - W-B ACC signal Engine switch on (ACC) 10 to 14 V ACCD (K73-11) - GND2 (K73-6) G - W-B ACC signal Engine switch off Below 1 V IG1D (K73-34) - GND2 (K73-6) SB - W-B IG1 signal Engine switch on (IG) 10 to 14 V IG1D (K73-34) - GND2 (K73-6) SB - W-B IG1 signal Engine switch on (ACC) Below 1 V IG2D (K73-35) - GND2 (K73-6) Y - W-B IG2 signal Engine switch on (IG) 10 to 14 V IG2D (K73-35) - GND2 (K73-6) Y - W-B IG2 signal Engine switch on (ACC) Below 1 V STP (K73-1) - GND2 (K73-6) V - W-B Stop light signal Brake pedal depressed 10 to 14 V STP (K73-1) - GND2 (K73-6) V - W-B Stop light signal Brake pedal released Below 1 V SLR+ (K73-32) - GND2 (K73-6) LG - W-B Steering lock motor signal Steering lock motor operating Below 1 V SLR+ (K73-32) - GND2 (K73-6) LG - W-B Steering lock motor signal Steering lock motor does not operate 10 to 14 V SLP (K73-26) - GND2 (K73-6) V - W-B Steering lock actuator position signal Steering lock is locked 10 to 14 V SLP (K73-26) - GND2 (K73-6) V - W-B Steering lock actuator position signal Steering lock is released Below 1 V SPD (K73-19) - GND2 (K73-6) L - W-B Vehicle speed signal Engine switch on (IG), rotate rear wheel slowly Pulse generation (see waveform 1) TACH (K73-2) - GND2 (K73-6) W - W-B Tachometer signal Engine running Pulse generation (see waveform 2) P (K73-5) - GND2 (K73-6) LG - W-B Shift lock signal Shift lever P position 10 to 14 V P (K73-5) - GND2 (K73-6) LG - W-B Shift lock signal Shift lever not P position Below 1 V CTSW (K73-31) - GND2 (K73-6) R - W-B Starter assist signal Brake pedal depressed, shift lever P position, engine switch is pushed once Below 1 V* 1 STSW (K73-39) - GND2 (K73-6) V - W-B Starter activation request signal Brake pedal depressed, shift lever P position, engine switch is pushed once 10 to 14 V* 2 STR1 (K73-17) - GND2 (K73-6) SB - W-B Park/neutral position switch Shift lever P position Below 1 V STR2 (K73-15) - GND2 (K73-6) L - W-B Starter signal Brake pedal depressed, shift lever P position, engine switch is pushed once 10 to 14 V* 2 INDS (K73-4) - GND2 (K73-6) SB - W-B Vehicle condition signal Brake pedal depressed, shift lever P position, engine switch on (ACC, IG) 10 to 14 V INDW (K73-13) - GND2 (K73-6) R - W-B Warning signal Brake pedal released, shift lever P position, engine switch on (ACC, IG) 10 to 14 V SWIL (K73-36) - GND2 (K73-6) GR - W-B Illumination signal Light control switch TAIL or HEAD 10 to 14 V SKSW (K73-28) - GND2 (K73-6) L - W-B Key in vehicle signal Engine switch on (ACC, IG) Below 1 V HINT: * 1 : Voltage is output only when the engine is cranking. * 2 : Voltage is output for 0.3 seconds after the engine start. If the result is not as specified, the ECU may have a malfunction. Using an oscilloscope, check the signal waveform of the ECU. WAVEFORM 1 (REFERENCE): Terminal No. K73-19 - Body ground Tool Setting 5 V/DIV., 10 msec./DIV. Vehicle Condition Driving at approx. 20 km/h (12 mph) HINT: As the vehicle speed increases, the wavelength shortens. WAVEFORM 2 (REFERENCE): Terminal No. K73-2 - Body ground Tool Setting 5 V/DIV., 10 msec./DIV. Vehicle Condition Engine idling HINT: As the vehicle speed increases, the wavelength shortens.
2. CHECK CERTIFICATION ECU Disconnect the U28 and U33 ECU connectors. Measure the voltage and resistance of the wire harness side connector. Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition +B1 (U28-1) - Body ground R - Body ground +B power supply Always 10 to 14 V IG (U28-18) - Body ground B - Body ground Ignition power supply Engine switch on (IG) 10 to 14 V IG (U28-18) - Body ground B - Body ground Ignition power supply Engine switch off Below 1 V LIN (U28-10) - Body ground LG - Body ground LIN line Always 10 kohms or higher E (U28-17) - Body ground W-B - Body ground Ground Always Below 1 ohms If the result is not as specified, there may be a malfunction on the wire harness side.
3. CHECK ECM Disconnect the A6, E6, E7, E8 and E45 ECM connectors. Measure the voltage and resistance of the wire harness side connectors. Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition +B (A6-6) - Body ground B-R - Body ground Power source of ECM Engine switch on (IG) 10 to 14 V +B1 (A6-5) - Body ground B-R - Body ground Power source of ECM Engine switch on (IG) 10 to 14 V IGSW (A6-17) - Body ground B-W - Body ground Ignition switch signal Engine switch on (IG) 10 to 14 V E01 (E6-2) - Body ground W-B - Body ground Ground Always Below 1 ohms E02 (E6-1) - Body ground W-B - Body ground Ground Always Below 1 ohms E03 (E8-6) - Body ground W-B - Body ground Ground Always Below 1 ohms E04 (E45-5) - Body ground W-B - Body ground Ground Always Below 1 ohms E05 (E45-3) - Body ground W-B - Body ground Ground Always Below 1 ohms E1 (E7-7) - Body ground BR - Body ground Ground Always Below 1 ohms EC (A6-2) - Body ground W-B - Body ground Ground Always Below 1 ohms ME01 (E8-4) - Body ground W-B - Body ground Ground Always Below 1 ohms If the result is not as specified, there may be a malfunction on the wire harness side. Reconnect the A6, E6, E7, E8 and E45 ECM connectors. Measure the voltage of the connectors. Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition STA (A6-12) - E1 (E7-7) R - BR Starter relay operation signal Cranking 10 to 14 V ACCR (A6-11) - E1 (E7-7) W-L - BR ACC relay cut signal (output) Engine switch on (IG) 10 to 14 V TACH (A7-16) - E1 (E7-7) W-L - BR Engine revolution signal (output) Idling Pulse generation (see waveform 1) STP (A7-4) - E1 (E7-7) R-B - BR Stop light switch signal (input) Brake pedal depressed 7.5 to 14 V STP (A7-4) - E1 (E7-7) R-B - BR Stop light switch signal (input) Brake pedal released Below 1.5 V STAR (E7-4) - E1 (E7-7) L-Y - BR PNP switch signal (input) Engine switch on (IG), shift position P or N 10 to 14 V KSW (A6-31) - E1 (E7-7) L - BR Engine switch signal (input) Engine switch off 4 to 6 V KSW (A6-31) - E1 (E7-7) L - BR Engine switch signal (input) Moment engine switch is pushed once 10 to 14 V KSW (A6-31) - E1 (E7-7) L - BR Engine switch signal (input) Engine switch on (ACC) Below 1.5 V If the result is not as specified, the ECM may have a malfunction. Using an oscilloscope, check the signal waveform of the ECM. WAVEFORM 1 (REFERENCE): Terminal No. A7-16 - Body ground Tool Setting 5 V/DIV., 10 msec./DIV. Vehicle Condition Engine idling HINT: As the vehicle speed increases, the wavelength shortens.
4. CHECK STEERING LOCK ECU Disconnect the K28 ECU connector. Measure the voltage and resistance of the wire harness side connector. Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition B (K28-7) - Body ground L - Body ground +B power supply Always Always IG2 (K28-6) - Body ground B - Body ground Ignition power supply Engine switch on (IG) Always IG2 (K28-6) - Body ground B - Body ground Ignition power supply Engine switch off Below 1 V GND (K28-1) - Body ground W-B - Body ground Ground Always Below 1 ohms SGND (K28-2) - Body ground W-B - Body ground Ground Always Below 1 ohms If the result is not as specified, there may be a malfunction on the wire harness side. Reconnect the K28 ECU connector. Measure the voltage of the connector. Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition SLP1 (K28-4) - GND (K28-1) V - W-B Steering lock actuator position signal Steering is locked 10 to 14 V SLP1 (K28-4) - GND (K28-1) V - W-B Steering lock actuator position signal Steering is released Below 1 V If the result is not as specified, the ECU may have a malfunction.

Scheme 66

1. DESCRIPTION Push-button start function data and the Diagnostic Trouble Codes (DTCs) can be read through the Data Link Connector 3 (DLC3) of the vehicle. When the function seems to be malfunctioning, use Techstream to check for malfunctions and perform repairs.
2. CHECK DLC3 HINT: The vehicle uses ISO 15765-4 communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 15765-4 format. Symbols (Terminal No.) Terminal Description Condition Specified Condition CG (4) - Body ground Chassis ground Always Below 1 ohms SG (5) - Body ground Signal ground Always Below 1 ohms SIL (7) - SG (5) Bus "+" line During transmission Pulse generation BAT (16) - Body ground Battery positive Always 10 to 14 V If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and connector. HINT: Connect the cable of Techstream to the DLC3, turn the engine switch on (IG) and attempt to use the tester. If the display indicates that a communication error has occurred, there is a problem either with the vehicle or with the tester. If communication is normal when the tester is connected to another vehicle, inspect the DLC3 of the original vehicle. If communication is still not possible when the tester is connected to another vehicle, the problem may be in the tester itself. Consult the Service Department listed in the tester's instruction manual.
3. INSPECT BATTERY VOLTAGE Standard voltage 11 to 14 V If the voltage is below 11 V, recharge or replace the battery before proceeding.

DTC CHECK / CLEAR

1. CHECK DTC Connect Techstream to the DLC3. Turn the engine switch on (IG). Read the DTC by following the prompts on the tester screen. HINT: Refer to Techstream operator's manual for further details.
2. CLEAR DTC Connect Techstream to the DLC3. Turn the engine switch on (IG). Erase the DTC by following the directions on the tester screen. HINT: Refer to Techstream operator's manual for further details.

DATA LIST / ACTIVE TEST

1. READ DATA LIST HINT: Using Techstream's DATA LIST allows switch, sensor, actuator and other item values to be read without removing any parts. Reading the DATA LIST early in troubleshooting is one way to save time. Connect Techstream to the DLC3. Turn the engine switch on (IG). Read the DATA LIST. Power source control ECU: Tester Display Measurement Item/Range Normal Condition Diagnostic Note Start Switch1 Start switch 1/ON or OFF ON: Engine switch on (IG) OFF: Engine switch off - Start Switch2 Start switch 2/ON or OFF ON: Engine switch on (IG) OFF: Engine switch off - Stop Light Switch1 Stop light switch 1/ON or OFF ON: Brake pedal depressed OFF: Brake pedal released - Stop Light Switch2 Stop light switch 2/ON or OFF ON: Brake pedal depressed OFF: Brake pedal released - IG1 Relay Monitor (Outside) IG1 outer relay monitor/ON or OFF ON: Engine switch on (IG) OFF: Engine switch off - IG1 Relay Monitor (Inside) IG1 inner relay monitor/ON or OFF ON: Engine switch on (IG) OFF: Engine switch off - IG2 Relay Monitor (Outside) IG2 outer relay monitor/ON or OFF ON: Engine switch on (IG) OFF: Engine switch off - IG2 Relay Monitor (Inside) IG2 inner relay monitor/ON or OFF ON: Engine switch on (IG) OFF: Engine switch off - ACC Relay Monitor ACC relay monitor/ON or OFF ON: Engine switch on (ACC) OFF: Engine switch off - Steering Unlock Switch Steering lock condition/ON or OFF ON: Steering is unlocked OFF: Steering is locked - Neutral SW / Clutch SW Neutral start switch/ON or OFF ON: Shift position is N OFF: Shift position is not N - Latch Circuit Latch circuit/ON or OFF ON: Engine switch on (IG) OFF: Engine switch off, on (ACC) or engine running - Starter Request Signal Starter request signal/ON or OFF ON: ST relay is ON OFF: ST relay is OFF - ACC Relay Cut Signal ACC relay cut signal/ON or OFF ON: Engine switch off OFF: Engine switch on (IG) - Vehicle Speed Signal Vehicle speed signal/STOP or RUN STOP: Vehicle is stopped RUN: Vehicle is running - Engine condition Engine condition/STOP or RUN STOP: Vehicle is stopped RUN: Vehicle is running - Power Supply Condition Power supply condition/ALL, ACC ON, IG1 IG2, ST ON ALL: All relays are ON ACC ON: ACC relay is ON IG1: IG1 relay is ON IG2: IG2 relay is ON ST ON: ST relay is ON - Number of Diagnosis Code Number of diagnosis codes/Min: 0, max: 255
2. PERFORM ACTIVE TEST HINT: Performing Techstream's ACTIVE TEST allows relay, VSV, actuator and other items be operated without removing any parts. Performing the ACTIVE TEST early in troubleshooting is one way to save time. The DATA LIST can be displayed during the ACTIVE TEST. Connect Techstream to the DLC3. Turn the engine switch on (IG). Perform the ACTIVE TEST according to the display on the tester. Power source control ECU: Tester Display Test Part Control Range Control Range Indicator for Lighting Indicator for lighting ON / OFF - Indicator Condition Indicator Green / Amber / No Sig - P Supply for Steering Lock Power supply for steering lock ECU ON / OFF

DIAGNOSTIC TROUBLE CODE CHART

PUSH-BUTTON START DTC

See also:
• INSPECTION