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

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1. CHECK POWER SOURCE MODE CHANGE FUNCTION Check the function of the engine switch. Check that power source mode changes in accordance with the conditions of the shift position and brake pedal. Brake Pedal Shift Lever Power Source Mode Pattern Depressed P or N Position When the engine switch is pushed once. off --> engine start Not depressed P position Each time the engine switch is pushed. off --> on (ACC) --> on (IG) --> off Except P Position Each time the engine switch is pushed. off --> on (ACC) --> on (IG) --> on (ACC) - P Position When the engine switch is pushed in the on (IG) condition. on (IG) --> off - Except P Position When the engine switch is pushed in the on (IG) condition. on (IG) --> on (ACC) Check if power source mode changes without pressing the engine switch. With power source mode on (ACC) and the shift position in P, wait for least 1 hour. Check that power source mode changes from on (ACC) to off automatically.
2. CHECK INDICATOR CONDITION Check the indicator on the engine switch. Check that the engine switch indicator illuminates and changes its color according to the table below. Power Source Mode/Condition Indicator Light Condition Brake pedal released Brake pedal depressed, shift lever in P or N off OFF Illuminates ON (Green) on (ACC, IG) Illuminates ON (Amber) Illuminates ON (Green) Engine running OFF OFF Steering lock not unlocked Flashes (Green) for 30 sec. Flashes (Green) for 30 sec. System malfunction Flashes (Amber) for 15 sec. Flashes (Amber) for 15 sec.

DESCRIPTION

This DTC is output when the IG output circuits inside the power source control ECU are open or short.

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1. INSPECT FUSE (AM2) Remove the AM2 fuse from the cowl side J/B RH. Measure the resistance of the fuse. Standard resistance Below 1 ohms NG --> REPLACE FUSE OK: Go to next step
2. CHECK WIRE HARNESS (POWER SOURCE CONTROL ECU BATTERY AND BODY GROUND) Disconnect the K73 ECU connector. Measure the voltage and resistance of the wire harness side connector. Standard voltage Tester Connection Specified Condition K73-33 (AM1) - Body ground 10 to 14 V K73-12 (AM2) - Body ground 10 to 14 V Standard resistance Tester Connection Specified Condition K73-6 (GND2) - Body ground Below 1 ohms NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK --> REPLACE POWER SOURCE CONTROL ECU

This DTC is output when a malfunction is occurring in the IG output circuit, which is from the IG1 relay actuation circuit inside the power source control ECU to the IG1 relay.

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1. CHECK WIRE HARNESS (COWL SIDE J/B RH - POWER SOURCE CONTROL ECU AND BODY GROUND) Disconnect the DA and DD J/B connectors. Disconnect the K73 ECU connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Specified Condition DD-6 - K73-34 (IG1D) Below 1 ohms DA-5 or DD-7 - Body ground Below 1 ohms DD-6 or K73-34 (IG1D) - Body ground 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
2. CHECK COWL SIDE J/B RH (RH-IG1 RELAY) Disconnect the DD and DM J/B connectors. Measure the resistance of the J/B connectors. Standard resistance Tester Connection Condition Specified Condition DM-1 - DD-14 When battery voltage is not applied to terminals DD-6 and DA-5 or DD-7 10 kohms or higher DM-1 - DD-14 When battery voltage is applied to terminals DD-6 and DA-5 or DD-7 Below 1 ohms NG --> REPLACE COWL SIDE J/B RH OK --> REPLACE POWER SOURCE CONTROL ECU

This DTC is output when a malfunction is occurring in the IG output circuit, which is from the IG2 relay actuation circuit inside the power source control ECU to the IG2 relay.

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1. INSPECT RELAY (Marking: IG2) Remove the IG2 relay from the engine room R/B No. 2. Measure the resistance of the relay. Standard resistance Tester Connection Specified Condition 3 - 5 10 kohms or higher 3 - 5 Below 1 ohms (when battery voltage is applied to terminals 1 and 2) NG --> REPLACE RELAY OK: Go to next step
2. CHECK WIRE HARNESS (ENGINE ROOM R/B NO. 2 - POWER SOURCE CONTROL ECU) Remove the IG2 relay from the engine room R/B No. 2. Disconnect the K73 ECU connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Specified Condition Engine room R/B No. 2 IG2 relay terminal 2 - K73-35 (IG2D) Below 1 ohms Engine room R/B No. 2 IG2 relay terminal 1 - Body ground Below 1 ohms NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK --> REPLACE POWER SOURCE CONTROL ECU

This DTC is output when a malfunction is occurring in the ACC output circuit, which is from the ACC relay actuation circuit inside the power source control ECU to the ACC relay.

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1. CHECK WIRE HARNESS (COWL SIDE J/B RH - POWER SOURCE CONTROL ECU AND BODY GROUND) Disconnect the DA and DD J/B connectors. Disconnect the K73 ECU connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Specified Condition DD-2 - K73-11 (ACCD) Below 1 ohms DA-5 - Body ground Below 1 ohms DD-7 - Body ground Below 1 ohms NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
2. CHECK COWL SIDE J/B RH (ACC RELAY) Disconnect the DD and DM J/B connectors. Measure the resistance of the J/B connectors. Standard resistance Tester Connection Condition Specified Condition DM-1 - DD-27 or DD-26 When battery voltage is not applied to terminals DD-2 and DD-7 or DA-5 10 kohms or higher DM-1 - DD-27 or DD-26 When battery voltage is applied to terminals DM-1 and DD-7 or DA-5 Below 1 ohms NG --> REPLACE COWL SIDE J/B RH OK --> REPLACE POWER SOURCE CONTROL ECU

This DTC is output when the ST output circuits inside the power source control ECU are open or short.

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1. CHECK WIRE HARNESS (POWER SOURCE CONTROL ECU - ECM) Disconnect the K73 ECU connector. Disconnect the A6 ECM connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Specified Condition K73-39 (STSW) - A6-19 (STSW) Below 1 ohms K73-39 (STSW) or A6-19 (STSW) - Body ground 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
2. CHECK AND REPLACE POWER SOURCE CONTROL ECU Temporarily replace the power source control ECU with a new or normally functioning one. Check that the engine starts normally. OK Engine starts normally. NG --> GO TO SFI SYSTEM OK --> REPLACE POWER SOURCE CONTROL ECU

This DTC is output when the ACCR output circuits inside the power source control ECU are open or short.

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1. CHECK WIRE HARNESS (POWER SOURCE CONTROL ECU - ECM) Disconnect the K73 ECU connector. Disconnect the A6 ECM connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Specified Condition K73-31 (CTSW) - A6-11 (ACCR) Below 1 ohms K73-31 (CTSW) or A6-11 (ACCR) - Body ground 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
2. CHECK AND REPLACE POWER SOURCE CONTROL ECU Temporarily replace the power source control ECU with a new or normally functioning one. Check that the engine starts normally. OK Engine starts normally. NG --> GO TO SFI SYSTEM OK --> REPLACE POWER SOURCE CONTROL ECU

This DTC is output when the submersion circuit monitor inside the power source control ECU detects that the vehicle is submerged in water.

This DTC is output when 1) a malfunction is detected between the power source control ECU and the engine switch; or 2) either of the switches inside the engine switch is malfunctioning.

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1. READ VALUE USING TECHSTREAM (START SWITCH 1 and 2) Check the DATA LIST for proper functioning of the start switch 1 and 2. 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 - OK ON (engine switch on (IG)) appears on the screen. NG --> See step 2 OK --> REPLACE POWER SOURCE CONTROL ECU
2. INSPECT ENGINE SWITCH Remove the engine switch. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Switch Condition Specified Condition 7 (SS1) - 5 (GND) Pushed Below 1 ohms 2 (SS2) - 5 (GND) Pushed Below 1 ohms 7 (SS1) - 5 (GND) Not pushed 10 kohms or higher 2 (SS2) - 5 (GND) Not pushed 10 kohms or higher NG --> REPLACE ENGINE SWITCH OK: Go to next step
3. CHECK WIRE HARNESS (ENGINE SWITCH - POWER SOURCE CONTROL ECU AND BODY GROUND) Disconnect the K29 switch connector. Disconnect the K73 ECU connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Specified Condition K29-7 (SS1) - K73-14 (SSW1) Below 1 ohms K29-2 (SS2) - K73-37 (SSW2) Below 1 ohms K29-5 (GND) - Body ground Below 1 ohms K29-7 (SS1) or K73-14 (SSW1) - Body ground 10 kohms or higher K29-2 (SS2) or K73-37 (SSW2) - Body ground 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK --> REPLACE POWER SOURCE CONTROL ECU

The power source control ECU and the shift lock control ECU are connected by a cable and the BEAN. If the cable information and BEAN information are inconsistent, this DTC will be output.

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1. CHECK WIRE HARNESS (POWER SOURCE CONTROL ECU SHIFT LOCK CONTROL ECU) Disconnect the K73 ECU connector. Disconnect the K39 ECU connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Specified Condition K73-5 (P) - K39-11 (P2) Below 1 ohms K73-5 (P) or K39-11 (P2) - Body ground 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
2. CHECK AND REPLACE POWER SOURCE CONTROL ECU Temporarily replace the power source control ECU with a new or normally functioning one. Check that the engine starts normally. OK Engine starts normally. NG --> GO TO SHIFT LOCK SYSTEM OK --> REPLACE POWER SOURCE CONTROL ECU

The power source control ECU and the combination meter are connected by a cable and the BEAN. DTC B2282 is output when: 1) the cable information and BEAN information are inconsistent; and 2) a malfunction is detected between the vehicle speed sensor and combination meter.

The skid control ECU converts these signals into 4-pulse signals and sends them to the combination meter. After this signal is converted into a more precise rectangular waveform by the waveform shaping circuit inside the combination meter, it is then transmitted to the power source control ECU. The power source control ECU determines the vehicle speed based on the frequency of these pulse signals.

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1. READ VALUE USING TECHSTREAM (VEHICLE SPEED SIGNAL) Check the DATA LIST for proper functioning of the vehicle speed signal. Power source control ECU Tester Display Measurement Item/Range Normal Condition Diagnostic Note Vehicle Speed Signal Vehicle speed signal/ STOP or RUN STOP: Vehicle is stopped RUN: Vehicle is running - OK STOP (vehicle is stopped) appears on screen. NG --> See step 2 OK --> REPLACE POWER SOURCE CONTROL ECU
2. CHECK WIRE HARNESS (POWER SOURCE CONTROL ECU - COMBINATION METER) Disconnect the K73 ECU connector. Disconnect the K31 meter connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Specified Condition K73-19 (SPD) - K31-9 (+S) Below 1 ohms K73-19 (SPD) or K31-9 (+S) - Body ground 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
3. CHECK AND REPLACE POWER SOURCE CONTROL ECU Temporarily replace the power source control ECU with a new or normally functioning one. Check that the engine starts normally. OK Engine starts normally. NG --> GO TO COMBINATION METER SYSTEM OK --> REPLACE POWER SOURCE CONTROL ECU

This DTC is output when: 1) the brake signal circuit between the power source control ECU and the stop light switch is malfunctioning; and 2) the BEAN information is inconsistent.

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1. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH) Check the DATA LIST for proper functioning of the stop light switch. Power source control ECU Tester Display Measurement Item/Range Normal Condition Diagnostic Note Stop Light Switch1 Stop light switch 1/ ON or OFF ON: Brake pedal depressed OFF: Brake pedal released - OK ON (brake pedal depressed) appears on screen. NG --> See step 2 OK --> REPLACE POWER SOURCE CONTROL ECU
2. INSPECT FUSE (STOP SW) Remove the STOP SW fuse from cowl side J/B RH. Measure the resistance of the fuse. Standard resistance Below 1 ohms NG --> REPLACE FUSE OK: Go to next step
3. INSPECT STOP LIGHT SWITCH Remove the switch. Measure the resistance of the switch. Standard resistance Tester Connection Condition Specified Condition 1 - 2 Switch pin not pushed Below 1 ohms 3 - 4 Switch pin not pushed 10 kohms or higher 1 - 2 Switch pin pushed 10 kohms or higher 3 - 4 Switch pin pushed Below 1 ohms NG --> REPLACE STOP LIGHT SWITCH OK: Go to next step
4. CHECK WIRE HARNESS (STOP LIGHT SWITCH - POWER SOURCE CONTROL ECU AND BATTERY) Disconnect the A35 switch connector. Disconnect the K73 ECU connector. Measure the voltage and resistance of the wire harness side connectors. Standard voltage Tester Connection Specified Condition A35-2 - Body ground 10 to 14 V Standard resistance Tester Connection Specified Condition A35-1 - K73-1 (STP) Below 1 ohms A35-1 or K73-1 (STP) - Body ground 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
5. CHECK AND REPLACE POWER SOURCE CONTROL ECU Temporarily replace the power source control ECU with a new or normally functioning one. Check that the engine starts normally. OK Engine starts normally. NG --> GO TO LIGHTING SYSTEM OK --> REPLACE POWER SOURCE CONTROL ECU

The power source control ECU and the steering lock ECU are connected by a cable and the LIN. These DTCs are output when: 1) the cable information and LIN information are inconsistent; and 2) a malfunction is detected between the power source control ECU and the steering lock ECU.

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1. READ VALUE USING TECHSTREAM (STEERING LOCK CONDITION) Check the DATA LIST for proper functioning of the steering lock condition. Power source control ECU Item Measurement Item/Display (Range) Normal Condition Diagnostic Note STR UNLOCK SW Steering lock condition/ ON or OFF ON: Steering is unlocked OFF: Steering is locked - OK ON (steering is unlocked) appears on the screen. NG --> See step 2 OK --> REPLACE POWER SOURCE CONTROL ECU
2. CHECK WIRE HARNESS (POWER SOURCE CONTROL ECU - STEERING LOCK ECU) Disconnect the K73 ECU connector. Disconnect the K28 ECU connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Specified Condition K73-26 (SLP) - K28-4 (SLP1) Below 1 ohms K73-26 (SLP) or K28-4 (SLP1) - Body ground 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
3. CHECK AND REPLACE POWER SOURCE CONTROL ECU Temporarily replace the power source control ECU with a new or normally functioning one. Check that the engine starts normally. OK Engine starts normally. NG --> GO TO STEERING LOCK SYSTEM OK --> REPLACE POWER SOURCE CONTROL ECU

The power source control ECU and the ECM are connected by a cable and the BEAN. If the cable information and BEAN information are inconsistent, this DTC will be output.

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1. READ VALUE USING TECHSTREAM (ENGINE CONDITION) Check the DATA LIST for proper functioning of the engine condition. Power source control ECU Tester Display Measurement Item/Range Normal Condition Diagnostic Note Engine Condition Engine condition/ RUN or STOP RUN: Engine running STOP: Engine stopped - OK RUN (engine running) appears on screen. STOP (engine stopped) appears on screen. NG --> See step 2 OK --> REPLACE POWER SOURCE CONTROL ECU
2. CHECK WIRE HARNESS (POWER SOURCE CONTROL ECU - ECM) Disconnect the K73 ECU connector. Disconnect the A7 ECM connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Specified Condition K73-2 (TACH) - A7-16 (TACH) Below 1 ohms K73-2 (TACH) or A7-16 (TACH) - Body ground 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
3. CHECK AND REPLACE POWER SOURCE CONTROL ECU Temporarily replace the power source control ECU with a new or normally functioning one. Check that the engine starts normally. OK Engine starts normally. NG --> GO TO SFI SYSTEM OK --> REPLACE POWER SOURCE CONTROL ECU

This DTC is output when: 1) any other DTC is set in the power source control ECU; or 2) the wire harness between the power source control ECU and the certification ECU is open or short.

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1. CHECK WIRE HARNESS (POWER SOURCE CONTROL ECU - CERTIFICATION ECU) Disconnect the K73 ECU connector. Disconnect the U28 ECU connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Specified Condition K73-30 (LIN1) - U28-10 (LIN) Below 1 ohms K73-30 (LIN1) or U28-10 (LIN) - Body ground 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK: Go to next step
2. CHECK AND REPLACE CERTIFICATION ECU Temporarily replace the certification ECU with a new or normally functioning one. Check for DTCs again. OK No DTC is output. NG --> REPLACE POWER SOURCE CONTROL ECU OK --> REPLACE CERTIFICATION ECU

If the certification ECU detects the key inside the vehicle when the shift lever position is P and the brake pedal is not depressed, each press of the engine switch changes the power source mode in the following order: off, on (ACC), on (IG), off. If one of the DTCs shown in the following illustration is detected, correct the DTCs according to the DTC chart. If the power source mode is still malfunctioning, one of the following may have occurred: 1) the MPX circuit has a malfunction, 2) the certification ECU has determined that the key is not inside the vehicle, 3) the engine switch has a malfunction, or 4) the power source control ECU has a malfunction.

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Engine start conditions or system malfunctions can be checked by the status of the engine switch indicator light.

ENGINE SWITCH INDICATOR LIGHT CONDITION

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1. INSPECT ENGINE SWITCH Remove the engine switch. Apply battery voltage between the terminals of the switch, and check the illumination condition of the switch. NOTE: If the positive (+) lead and the negative (-) lead are incorrectly connected, the engine switch indicator does not illuminate. If the voltage is too low, the indicator will not illuminate. OK Measurement Condition Specified Condition Battery positive (+) --> Terminal 11 (SWIL) Battery negative (-) --> Terminal 4 (COM) or 5 (GND) Illuminates Battery positive (+) --> Terminal 12 (INDS) Battery negative (-) --> Terminal 4 (COM) or 5 (GND) Illuminates Battery positive (+) --> Terminal 13 (INDW) Battery negative (-) --> Terminal 4 (COM) or 5 (GND) Illuminates NG --> REPLACE ENGINE SWITCH OK: Go to next step
2. CHECK WIRE HARNESS (ENGINE SWITCH - POWER SOURCE CONTROL ECU AND BODY GROUND) Disconnect the K29 switch connector. Disconnect the K73 ECU connector. Measure the resistance of the wire harness side connectors. Standard resistance Tester Connection Specified Condition K29-11 (SWIL) - K73-36 (SWIL) Below 1 ohms K29-12 (INDS) - K73-4 (INDS) Below 1 ohms K29-13 (INDW) - K73-13 (INDW) Below 1 ohms K29-5 (GND) - Body ground Below 1 ohms K29-4 (COM) - Body ground Below 1 ohms K29-11 (SWIL) or K73-36 (SWIL) - Body ground 10 kohms or higher K29-12 (INDS) or K73-4 (INDS) - Body ground 10 kohms or higher K29-13 (INDW) or K73-13 (INDW) - Body ground 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS AND CONNECTOR OK --> REPLACE POWER SOURCE CONTROL ECU