Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Cruise Control Switch Circuit

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Engine & Hybrid System / Cruise Control / Dynamic Radar Cruise Control System / Cruise Control Switch Circuit

DESCRIPTION

The cruise control main switch is used to turn the dynamic radar cruise control system on and off, as well as operate 7 functions: SET, - (COAST), TAP-DOWN, RES (RESUME), + (ACCEL), TAP-UP and CANCEL.

The SET, TAP-DOWN and - (COAST) functions, and the RES (RESUME), TAP-UP and + (ACCEL) functions are operated with the same switch. The cruise control main switch contains momentary type contacts for each function. The contacts close only while the cruise control main switch is being operated in the direction of the relative function arrow, and open when the cruise control main switch is released. The voltage at the terminal of the ECM changes as each of the different contacts open or close. The ECM reads this voltage and controls the SET, - (COAST), RES (RESUME), + (ACCEL), and CANCEL functions accordingly.

  • Vehicle-to-vehicle distance control mode is selected by default when the dynamic radar cruise control system is turned on using the cruise control main switch (ON/OFF button).

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Before replacing the ECM, refer to Registration.

    Click here

  • The vehicle is equipped with a Supplemental Restraint System (SRS) which includes components such as airbags. Before servicing (including removal or installation of parts), be sure to read the precaution for Supplemental Restraint System.

    Click here

PROCEDURE

1.

READ VALUE USING TECHSTREAM

(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 / Radar Cruise 1 / Data List.

(e) Read the Data List according to the display on the Techstream.

Powertrain > Cruise Control > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

-SET Switch

-SET switch status

OFF or ON

OFF: -SET switch off

ON: -SET switch on

-

+RES Switch

+RES switch status

OFF or ON

OFF: +RES switch off

ON: +RES switch on

-

Cruise Main Switch Operation Condition

Cruise control main switch status

OFF or ON

OFF: Cruise control main switch (ON-OFF) off

ON: Cruise control main switch (ON-OFF) on

-
Powertrain > Cruise Control > Data List

Tester Display

-SET Switch

+RES Switch

Cruise Main Switch Operation Condition

OK:

The Data List items shown in the table change according to the operation of the cruise control main switch.

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

2.

INSPECT CRUISE CONTROL MAIN SWITCH

(a) Remove the cruise control main switch.

Click here

(b) Inspect the cruise control main switch.

Click here

NG

REPLACE CRUISE CONTROL MAIN SWITCH

OK

3.

INSPECT STEERING PAD SWITCH ASSEMBLY

(a) Remove the steering pad switch assembly.

Click here

(b) Inspect the steering pad switch assembly.

Click here

NG

REPLACE STEERING PAD SWITCH ASSEMBLY

OK

4.

INSPECT SPIRAL CABLE SUB-ASSEMBLY

(a) Remove the spiral cable sub-assembly.

Click here

(b) Inspect the spiral cable sub-assembly.

Click here

NG

REPLACE SPIRAL CABLE SUB-ASSEMBLY

OK

5.

CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - ECM AND BODY GROUND)

(a) Disconnect the A37 ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J29-7 (CCS) - A37-41 (CCS)

Always

Below 1 Ω

J29-2 (ECC) - Body ground

Always

Below 1 Ω

J29-7 (CCS) or A37-41 (CCS) - Body ground

Always

10 kΩ or higher
OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
    Invalid Data Received from ECM/PCM "A" Invalid Serial Data Received (U040181)
    DESCRIPTION If the ECM cannot recognize the forward recognition camera. DTC U040181 is stored. DTC No. Detection Item DTC Detection Condition Trouble Area MIL DTC Output from U040181 ...

    Distance Control Switch Circuit
    DESCRIPTION The vehicle-to-vehicle distance control switch is used to set the distance for vehicle-to-vehicle distance control mode. The vehicle-to-vehicle distance control switch is installed in the ...

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

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

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