Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Brake Pressure Sensor "A" Circuit Voltage Above Threshold (C054017)

DESCRIPTION

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
C054017	Brake Pressure Sensor "A" Circuit Voltage Above Threshold	When vehicle speed exceeds 3 km/h (2 mph) and stop light switch assembly is OFF, master cylinder pressure continuously exceeds 1.764 MPa (18.0 kgf/cm2, 255 psi) for 5 seconds or more.	Wire harness and connector Stop light switch assembly Master cylinder pressure sensor (Brake actuator assembly) Master cylinder pressure sensor circuit malfunction Skid control ECU (Brake actuator assembly)

WIRING DIAGRAM

Click here

CAUTION / NOTICE / HINT

PROCEDURE

1.

CLEAR DTC

(a) Connect the Techstream to the DLC3.

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

(c) Operate the Techstream to clear the codes. Enter the following menus: Chassis / Brake/EPB / Trouble Codes.

Chassis > Brake/EPB > Clear DTCs

(d) Press the DTC clear button.

(e) Turn the engine switch off.

NEXT

2.	RECONFIRM DTC

(a) Start the engine.

(b) Perform a road test.

(c) Read the DTCs following the prompts on the Techstream. Enter the following menus: Chassis / Brake/EPB / Trouble Codes.

Chassis > Brake/EPB > Trouble Codes

(d) Check if the same DTC is output.

Result	Proceed to
DTC C054017 is output	A
DTCs C054017 and P057113 are output	B

B

GO TO DTC CHART (P057113)

A

3.	READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH ASSEMBLY)

(a) Enter the following menus: Chassis / Brake/EPB / Data List.

Chassis > Brake/EPB > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Stop Light SW	Stop light switch assembly (STP terminal input)	OFF / ON	OFF: Brake pedal released ON: Brake pedal depressed	HINT: The brake pedal state is determined using the voltage at terminal STP

Chassis > Brake/EPB > Data List

Tester Display
Stop Light SW

(b) Check that the stop light switch assembly condition observed on the Techstream changes according to brake pedal operation.

OK:

The Techstream displays OFF / ON according to brake pedal operation.

NG

GO TO STEP 7

OK

4.	READ VALUE USING TECHSTREAM (MASTER CYLINDER SENSOR)

(a) Enter the following menus: Chassis / Brake/EPB / Data List.

Chassis > Brake/EPB > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Master Cylinder Sensor 1	Master cylinder pressure sensor pressure (value detected by ECU)	Min.: -1.00 MPa Max.: 23.99 MPa	Brake pedal released: -1.00 to 0.00 MPa	Reading increases when brake pedal is depressed

Chassis > Brake/EPB > Data List

Tester Display
Master Cylinder Sensor 1

(b) Start the engine.

(c) Check the value of Data List item Master Cylinder Sensor 1 when the brake pedal is released.

OK:

The value of Data List item Master Cylinder 1 is within standard range.

NG

REPLACE BRAKE ACTUATOR ASSEMBLY

OK

5.

CLEAR DTC

(a) Operate the Techstream to clear the codes. Enter the following menus: Chassis / Brake/EPB / Trouble Codes.

Chassis > Brake/EPB > Clear DTCs

(b) Press the DTC clear button.

(c) Turn the engine switch off.

NEXT

6.	RECONFIRM DTC

(a) Start the engine.

(b) Drive the vehicle and perform a braking test (decelerate the vehicle by depressing the brake pedal).

(c) Read the DTCs following the prompts on the Techstream. Enter the following menus: Chassis / Brake/EPB / Trouble Codes.

Chassis > Brake/EPB > Trouble Codes

(d) Check if the same DTC is output.

Result	Proceed to
DTC C054017 is not output.	A
DTC C054017 is output.	B

A

USE SIMULATION METHOD TO CHECK

B

REPLACE BRAKE ACTUATOR ASSEMBLY

7.	CHECK STOP LIGHT SWITCH ASSEMBLY INSTALLATION

(a) Turn the engine switch off.

(b) Check the stop light switch assembly installation.

Click here

OK:

The stop light switch assembly installation are normal.

NG

INSTALL STOP LIGHT SWITCH ASSEMBLY CORRECTLY

OK

8.	INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) Inspect the stop light switch assembly.

Click here

OK:

The stop light switch assembly is normal.

NG

REPLACE STOP LIGHT SWITCH ASSEMBLY

OK

9.	CHECK HARNESS AND CONNECTOR (STP TERMINAL)

(a) Make sure that there is no looseness at the locking part and the connecting part of the connectors. OK: The connector is securely connected.

*a Front view of wire harness connector (to Skid Control ECU (Brake Actuator Assembly))

(b) Disconnect the A41 skid control ECU (brake actuator assembly) connector.

(c) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A41-11 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	8 to 14 V
A41-11 (STP) - Body ground	Stop light switch assembly off (Brake pedal released)	Below 1.5 V

OK

REPLACE BRAKE ACTUATOR ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR