Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Test Mode Procedure

HINT:

• Signals related to the vehicle stability control system can be inspected by performing a Dealer Mode (Signal Check) inspection. During the inspection, the display of items determined normal by the skid control ECU (brake actuator assembly) changes from incomplete to complete.
• During Dealer Mode (Signal Check), the VSC system does not operate regardless of whether the system is normal or a malfunction is detected.
• When a malfunction occurs in an ABS system sensor, the ABS warning light illuminates.
• When a malfunction occurs in a VSC system sensor, the slip indicator light illuminates.
• When entering Dealer Mode (Signal Check), the skid control ECU communicates with the forward recognition camera to judge whether the vehicle is equipped with the pre-collision system. Therefore, do not exit Dealer Mode (Signal Check) within 5 seconds of entering Dealer Mode (Signal Check).

HINT:

• If the ABS warning light or slip indicator light remains illuminated or does not illuminate when Dealer Mode (Signal Check) is entered, a component or wire harness may be malfunctioning.
• When entering Dealer Mode (Signal Check), if the parking brake is engaged, the parking brake indicator light (red) will illuminate, and if the parking brake is not engaged, the parking brake indicator light (red) will blink in the Dealer Mode pattern (blinking at 0.25 seconds intervals).

NOTICE:

• If the brake pedal is depressed slowly or repeatedly, the master cylinder pressure sensor zero point calibration will not complete normally.
• If the lost booster pressure judgment check results are not normal, then the master cylinder pressure sensor check cannot be performed.
• If rechecking after the engine has started, end Test Mode, enter Test Mode again, and release vacuum in the booster by pumping the brake pedal prior to rechecking.

HINT:

• The status of the ABS warning light and slip indicator light will not change.
• If the master cylinder pressure sensor is normal and the above step is performed when in Dealer Mode (Signal Check), the master cylinder pressure sensor check will complete normally.

NOTICE:

• If the sensor check does not complete successfully or a malfunctioning sensor is detected, the ABS warning light indicates the Dealer Mode pattern (blinking at 0.25 seconds intervals) and the ABS system will not operate.
• If the vehicle is driven at 80 km/h (50 mph) or more after the ABS warning lamp turns off, the speed sensor check will be performed again. In this situation, the ABS warning lamp will start blinking again.
• The speed sensor check may not complete if the sensor check is started with the steering wheel turned or one or more wheels spinning.

NOTICE:

• When Dealer Mode (Signal Check) is started with the Techstream and all items display complete, the sensor check ends.
• If the sensor checks have not completed, the ABS warning light will remain blinking while the vehicle is being driven, and the ABS will not operate.
• If a DTC is detected in Dealer Mode (Signal Check), the ABS warning light or slip indicator light illuminates.
• If any DTCs are output or if Dealer Mode (Signal Check) items do not complete even after repeated attempts, repair or replace the malfunctioning part.

Check For Intermittent Problems

CHECK FOR INTERMITTENT PROBLEMS CHECK FOR INTERMITTENT PROBLEMS HINT: A momentary interruption (open circuit) in the connectors and/or wire harness between the sensors and ECUs can be detected using t ...

Problem Symptoms Table

PROBLEM SYMPTOMS TABLE If there are no DTCs output and the problem still occurs, check the suspected areas for each problem symptom in the order given in the following table and proceed to the relevan ...

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