Last Modified: 04-05-2023 |
6.11:8.1.0 |
Doc ID: RM1000000018KEQ |
Model Year Start: 2018 |
Model: Sienna |
Prod Date Range: [11/2017 -
] |
Title: BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: C1426; Stop Light Switch OFF Stuck Malfunction; 2018 - 2020 MY Sienna [11/2017 - ] |
DTC
|
C1426
|
Stop Light Switch OFF Stuck Malfunction
|
DESCRIPTION
The skid control ECU (brake actuator assembly) inputs stop light switch signals and the condition of brake operation.
The skid control ECU (brake actuator assembly) has an open detection circuit, which outputs this DTC when detecting an open in the stop light input line or the ground line of the stop light circuit with the stop light switch off (brake pedal not depressed).
DTC No.
|
DTC Detection Condition
|
Trouble Area
|
C1426
|
When the brake pedal load sensing switch is on, the master cylinder pressure is 2 MPa (20.4 kgf/cm2, 290 psi) or more and the deceleration calculated from the vehicle speed is 0.2 G or more, the stop light switch assembly is off for 2 seconds or more.
|
-
Wire harness or connector
-
Stop light switch assembly
-
Brake pedal load sensing switch (brake pedal support assembly)
-
Skid control ECU (brake actuator assembly)
|
WIRING DIAGRAM
Refer to DTCs C1425 (See page
).
CAUTION / NOTICE / HINT
NOTICE:
-
When replacing the skid control ECU (brake actuator assembly), perform zero point calibration and store system information (See page
).
-
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
PROCEDURE
1.
|
CHECK BRAKE PEDAL HEIGHT AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION
|
(a) Check the brake pedal height and stop light switch assembly installation (See page
).
OK:
The brake pedal height and stop light switch assembly installation are normal.
HINT:
If the on/off status of the stop light switch assembly and the pressure increase information from the master cylinder pressure sensor do not match due to an improperly installed brake pedal or stop light switch assembly, this DTC may be stored. Therefore, be sure to check the installation condition of the pedal and stop light switch assembly before inspecting the input signals and other related parts.
OK
|
|
|
2.
|
CHECK STOP LIGHT OPERATION
|
(a) Check that the stop lights come on when the brake pedal is depressed, and go off when the brake pedal is released.
OK:
Condition
|
Illumination Condition
|
Brake pedal depressed.
|
ON
|
Brake pedal released.
|
OFF
|
OK
|
|
|
3.
|
READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH ASSEMBLY AND BRAKE PEDAL LOAD SENSING SWITCH)
|
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Select the Data List using the Techstream (See page
).
ABS/VSC/TRAC
Tester Display
|
Measurement Item/Range
|
Normal Condition
|
Diagnostic Note
|
Stop Light SW
|
Stop light switch assembly / ON or OFF
|
ON: Brake pedal depressed
OFF: Brake pedal released
|
-
|
Brake Pedal Load Sensing SW
|
Brake pedal load sensing switch / ON or OFF
|
ON: Brake pedal depressed beyond a specified point
OFF: Brake pedal not depressed beyond a specified point
|
-
|
(e) Check that the stop light switch assembly display and brake pedal load sensing switch display observed on the Techstream change according to brake pedal operation.
OK:
The Techstream displays ON or OFF according to brake pedal operation.
(f) Slowly depress the brake pedal, and check when the stop light switch assembly and brake pedal load sensing switch turn on.
OK:
First the stop light switch assembly should turn on, and then the brake pedal load sensing switch should turn on.
Result
|
Proceed to
|
OK
|
A
|
NG (The stop light switch assembly does not turn on.)
|
B
|
NG (Turning on of the brake pedal load sensing switch is not confirmed.)
|
C
|
NG (The brake pedal load sensing switch turns on first.)
|
D
|
A
|
|
|
(a) Turn the ignition switch off.
(b) Clear the DTCs (See page
).
(c) Turn the ignition switch off.
(d) Start the engine.
(e) Depress the brake pedal several times to test the stop light circuit.
(f) Check if the same DTC is output (See page
).
Result
|
Proceed to
|
DTC C1426 is not output.
|
A
|
DTC C1426 is output.
|
B
|
HINT:
If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step (See page
).
5.
|
INSPECT STOP LIGHT SWITCH ASSEMBLY
|
(a) for Bulb Type Stop Light
(1) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
|
Switch Condition
|
Specified Condition
|
1 - 2
|
Switch pin released
|
Below 1 Ω
|
Switch pin pushed in
|
10 kΩ or higher
|
Text in Illustration
*a
|
Component without harness connected
(Stop Light Switch Assembly)
|
|
|
(b) for LED Type Stop Light
(1) Reconnect the stop light switch assembly connector.
(2) Measure the resistance according to the value(s) in the table below.
Standard Voltage:
Tester Connection
|
Switch Condition
|
Specified Condition
|
A59-2 (L) - A59-3 (GND)
|
Switch pin released
|
8 to 14 V
|
Switch pin pushed in
|
Below 1.5 V
|
Text in Illustration
*a
|
Component with harness connected
(Stop Light Switch Assembly)
|
Result
Result
|
Proceed to
|
OK (w/ Toyota Safety Sense P)
|
A
|
OK (w/o Toyota Safety Sense P)
|
B
|
NG
|
C
|
|
|
A
|
|
|
6.
|
CHECK HARNESS AND CONNECTOR (SWITCH INPUT TERMINAL)
|
(a) Turn the ignition switch off.
(b) Remove the STOP LP relay.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection
|
Switch Condition
|
Specified Condition
|
STOP LP relay terminal 4 - Body ground
|
Stop light switch assembly ON (Brake pedal depressed)
|
8 to 14 V
|
STOP LP relay terminal 4 - Body ground
|
Stop light switch assembly OFF (Brake pedal released)
|
Below 1.5 V
|
Text in Illustration
*1
|
Engine Room Relay Block
|
*2
|
STOP LP Relay Holder
|
|
|
NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR (SWITCH INPUT CIRCUIT)
|
OK
|
|
|
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
|
Condition
|
Specified Condition
|
3 - 4
|
Voltage is not applied between terminals 1 and 2
|
Below 1 Ω
|
3 - 4
|
Voltage is applied between terminals 1 and 2
|
10 kΩ or higher
|
Text in Illustration
|
|
NG |
|
REPLACE STOP LP RELAY
|
OK
|
|
|
8.
|
CHECK HARNESS AND CONNECTOR (STP TERMINAL)
|
(a) Turn the ignition switch off.
(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
(c) Disconnect the skid control ECU (brake actuator assembly) connector.
(d) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection
|
Condition
|
Specified Condition
|
A75-35 (STP) - Body ground
|
Stop light switch assembly on (Brake pedal depressed)
|
8 to 14 V
|
A75-35 (STP) - Body ground
|
Stop light switch assembly off (Brake pedal released)
|
Below 1.5 V
|
Text in Illustration
*a
|
Front view of wire harness connector
(to Skid Control ECU (Brake Actuator Assembly))
|
HINT:
If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts (See page
).
|
|
NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)
|
OK
|
|
|
(a) Turn the ignition switch off.
(b) Reconnect the A75 skid control ECU (brake actuator assembly) connector.
(c) Clear the DTCs (See page
).
(d) Turn the ignition switch off.
(e) Start the engine.
(f) Depress the brake pedal several times to test the stop light circuit.
(g) Check if the same DTC is output (See page
).
Result
Result
|
Proceed to
|
DTC C1426 is not output.
|
A
|
DTC C1426 is output.
|
B
|
HINT:
If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step (See page
).
10.
|
CHECK HARNESS AND CONNECTOR (STP TERMINAL)
|
(a) Turn the ignition switch off.
(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.
(c) Disconnect the skid control ECU (brake actuator assembly) connector.
(d) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection
|
Switch Condition
|
Specified Condition
|
A75-35 (STP) - Body ground
|
Stop light switch assembly ON (Brake pedal depressed)
|
8 to 14 V
|
A75-35 (STP) - Body ground
|
Stop light switch assembly OFF (Brake pedal released)
|
Below 1.5 V
|
Text in Illustration
*a
|
Front view of wire harness connector
(to Skid Control ECU (Brake Actuator Assembly))
|
HINT:
If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts (See page
).
|
|
NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)
|
OK
|
|
|
11.
|
CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)
|
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
|
Condition
|
Specified Condition
|
A75-25 (GND1) - Body ground
|
Always
|
Below 1 Ω
|
Text in Illustration
*a
|
Front view of wire harness connector
(to Skid Control ECU (Brake Actuator Assembly))
|
HINT:
If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts (See page
).
|
|
NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)
|
12.
|
INSPECT BRAKE PEDAL LOAD SENSING SWITCH (BRAKE PEDAL SUPPORT ASSEMBLY)
|
(a) Turn the ignition switch off.
(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
(c) Disconnect the A7 brake pedal load sensing switch (brake pedal support assembly) connector.
NOTICE:
-
Do not remove the brake pedal load sensing switch from the brake pedal support assembly.
-
When there is a malfunction in the brake pedal load sensing switch, replace the brake pedal support assembly.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
|
Condition
|
Specified Condition
|
2 - 1
|
Brake pedal load sensing switch off
(Brake pedal depressed)
|
950 to 1050 Ω
|
2 - 1
|
Brake pedal load sensing switch on
(Brake pedal released)
|
203 to 223 Ω
|
Text in Illustration
*a
|
Component without harness connected
(Brake Pedal Load Sensing Switch (Brake Pedal Support Assembly))
|
|
|
OK
|
|
|
13.
|
CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - BRAKE PEDAL SUPPORT ASSEMBLY)
|
(a) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
(b) Disconnect the A75 skid control ECU (brake actuator assembly) connectors.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
|
Condition
|
Specified Condition
|
A75-23 (FSW+) - A7-2
|
Always
|
Below 1 Ω
|
A75-23 (FSW+) - Body ground
|
Always
|
10 kΩ or higher
|
A7-1 - Body ground
|
Always
|
Below 1 Ω
|
HINT:
If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts (See page
).
NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR
|
|