Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual: Starter Signal Circuit

Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual / Engine & Hybrid System / 2gr-fks (engine Control) / Sfi System / Starter Signal Circuit

DESCRIPTION

While the engine is being cranked, current flows from terminal STAR of the certification ECU (smart key ECU assembly) to the park/neutral position switch assembly and to terminal STA of the ECM (STA signal).

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

CHECK WHETHER ENGINE CAN BE CRANKED

(a) Check if the engine can be cranked.

Result

Proceed to

Engine cannot be cranked

A

Engine can be cranked

B
B

GO TO STEP 12

A

2.

READ VALUE USING TECHSTREAM (STARTER SW)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / Starter SW.

Powertrain > Engine > Data List

Tester Display

Starter SW

(e) Check the value displayed on the Techstream when the engine switch is turned on (IG) and the engine is cranked.

OK:

Condition

Techstream Display (Starter SW)

Engine switch on (IG)

OFF

Cranking position

ON
NG

GO TO STEP 9

OK

3.

INSPECT RELAY (ST RELAY)

(a) Inspect the ST relay.

Click here

NG

REPLACE RELAY (ST RELAY)
OK

4.

INSPECT STARTER ASSEMBLY

(a) Inspect the starter assembly.

Click here

NG

REPLACE STARTER ASSEMBLY

OK

5.

CHECK HARNESS AND CONNECTOR (ST RELAY - STARTER ASSEMBLY)

(a) Remove the ST relay from the engine room relay block and junction block assembly.

(b) Disconnect the starter assembly connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

3 (ST relay) - D21-1 (ST)

Always

Below 1 Ω

3 (ST relay) or D21-1 (ST) - Body ground and other terminals

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

6.

CHECK HARNESS AND CONNECTOR (ST RELAY - BODY GROUND)

(a) Remove the ST relay from the engine room relay block and junction block assembly.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

1 (ST relay) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

7.

CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH ASSEMBLY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ST RELAY)

(a) Disconnect the park/neutral position switch assembly connector.

(b) Disconnect the certification ECU (smart key ECU assembly) connector.

(c) Remove the ST relay from the engine room relay block and junction block assembly.

(d) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

D15-9 (L) - 2 (ST relay)

Always

Below 1 Ω

A74-20 (STA) - 2 (ST relay)

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

8.

CHECK HARNESS AND CONNECTOR (BATTERY - ST RELAY)

(a) Remove the ST relay from the engine room relay block and junction block assembly.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

5 (ST relay) - Body ground

Always

11 to 14 V
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - STARTER ASSEMBLY)
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

9.

INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY

(a) Inspect the park/neutral position switch assembly.

  • for 2WD models: Click here
  • for AWD models: Click here
NG

REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY
OK

10.

CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH ASSEMBLY - ECM - ST RELAY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))

(a) Disconnect the park/neutral position switch assembly connector.

(b) Disconnect the ECM connector.

(c) Remove the ST relay from the engine room relay block and junction block assembly.

(d) Disconnect the certification ECU (smart key ECU assembly) connector.

(e) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

D15-9 (L) - A37-43 (STA)

Always

Below 1 Ω

D15-9 (L), A37-43 (STA), 2 (ST relay) or A74-20 (STA) - Body ground and other terminals

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

11.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - PARK/NEUTRAL POSITION SWITCH ASSEMBLY - ECM)

(a) Disconnect the park/neutral position switch assembly connector.

(b) Disconnect the certification ECU (smart key ECU assembly) connector.

(c) Disconnect the ECM connector.

(d) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

A74-9 (STAR) - D15-4 (B)

Always

Below 1 Ω

A74-9 (STAR) - D2-106 (NSW)

Always

Below 1 Ω

A74-9 (STAR), D15-4 (B) or D2-106 (NSW) - Body ground and other terminals

Always

10 kΩ or higher
OK

GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

12.

READ VALUE USING TECHSTREAM (STARTER SW)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / Starter SW.

Powertrain > Engine > Data List

Tester Display

Starter SW

(e) Check the value displayed on the Techstream when the engine switch is turned on (IG) and the engine is cranked.

OK:

Condition

Techstream Display (Starter SW)

Engine switch on (IG)

OFF

Cranking position

ON
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (ST RELAY - ECM)
    Fuel Pump Control Circuit
    DESCRIPTION The fuel pump (for low pressure side) circuit consists of the ECM, fuel pump (for low pressure side) and fuel pump control ECU assembly (which operates the fuel pump (for low pressure side ...

    VC Output Circuit
    DESCRIPTION The ECM constantly generates a 5 V power source voltage from the battery voltage supplied to the +B, +B2 (BATT) terminals to operate the microprocessor. The ECM also provides this power to ...

    Other materials:

    Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual > Rear Differential Carrier Oil Seal: Components
    COMPONENTS ILLUSTRATION *1 DIAPHRAGM OIL SEAL *2 ELECTRO MAGNETIC CONTROL COUPLING SUB-ASSEMBLY *3 ELECTRO MAGNETIC CONTROL COUPLING WIRE HARNESS *4 TRANSMISSION COUPLING CONICAL SPRING WASHER *5 TRANSMISSION COUPLING SPACER *6 REAR DIFFERENTIAL DRAIN PLUG *7 DIFF ...

    Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual > Blind Spot Monitor System: Vehicle Speed Sensor (C1A45)
    DESCRIPTION The blind spot monitor sensor receives vehicle speed signals from the skid control ECU via CAN communication. DTC No. Detection Item DTC Detection Condition Trouble Area C1A45 Vehicle Speed Sensor A fail flag is transmitted from the skid control ECU Vehicle stabilit ...

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual

    © 2024 Copyright www.lexusrx.net
    0.0194