DTC P0504: Brake Switch "A" / "B" Correlation [09/2014 - 11/2017]: Procedure
WARNING: This page is about a different car, the 2017 Lexus RC 350, 2017 Lexus RC 300, 2016 Lexus RC 350, 2016 Lexus RC 300, and 2015 Lexus RC 350. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK TERMINAL VOLTAGE (POWER SOURCE OF STOP LIGHT SWITCH ASSEMBLY)
*a Front view of wire harness connector
(to Stop Light Switch Assembly)- Disconnect the stop light switch assembly connector.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition A52-1 (B) - Body ground Always 11 to 14 V Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - STOP LIGHT SWITCH ASSEMBLY)
Result:
OK
See step 2
- CHECK TERMINAL VOLTAGE (POWER SOURCE OF STOP LIGHT SWITCH ASSEMBLY)
*a Front view of wire harness connector
(to Stop Light Switch Assembly)- Disconnect the stop light switch assembly connector.
- Turn the engine switch on (IG).
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition A52-5 (B) - Body ground Engine switch on (IG) 11 to 14 V Result
Proceed to OK NG
Result:
NG
See step 6
Result:
OK
See step 3
- CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BODY GROUND)
- Disconnect the stop light switch assembly connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A52-3 (GND) - Body ground Always Below 1 Ω Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
Result:
OK
See step 4
- CHECK TERMINAL VOLTAGE (STP AND ST1- VOLTAGE)
*a Brake Pedal Depressed *b Brake Pedal Released *c Component with harness connected
(ECM)- Turn the engine switch on (IG).
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Brake Pedal Operation Specified Condition A70-12 (ST1-) - Body ground Released 7.5 to 14 V Depressed Below 1.5 V A70-13 (STP) - Body ground Released Below 1.5 V Depressed 7.5 to 14 V Result
Proceed to OK NG
Result:
OK
REPLACE ECM. Refer to REMOVAL [09/2014 - 11/2017]
Result:
NG
See step 5
- CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - ECM)
- Disconnect the stop light switch assembly connector.
- Disconnect the ECM connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A52-4 (L) - A70-12 (ST1-) Always Below 1 Ω A52-2 (L) - A70-13 (STP) Always Below 1 Ω A52-4 (L) or A70-12 (ST1-) - Body ground Always 10 kΩ or higher A52-2 (L) or A70-13 (STP) - Body ground Always 10 kΩ or higher Result
Proceed to OK NG
Result:
OK
REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to REMOVAL [09/2014 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
- CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - SEMICONDUCTOR PWR INTEGRATION ECU)
- Disconnect the stop light switch assembly connector.
- Disconnect the semiconductor pwr integration ECU connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A52-5 (B) - 2F-4 Always Below 1 Ω A52-5 (B) or 2F-4 - Body ground Always 10 kΩ or higher Result
Proceed to OK NG
Result:
OK
REPLACE SEMICONDUCTOR POWER INTEGRATION ECU. Refer to REMOVAL [09/2014 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR