DESCRIPTION The skid
control ECU (brake booster with master cylinder assembly) detects the
brake operating conditions through a signal transmitted by the stop
light switch assembly. The skid control ECU
incorporates a circuit to detect an open circuit. This DTC is output
when an open circuit is detected in the stop light signal input line. |
DTC No. | Detection Item |
INF Code | DTC Detection Condition |
Trouble Area | MIL |
Note | | C1425 |
Open in Stop Switch Circuit |
231 | An open stop light switch circuit continues for 10 seconds or more. |
- Wire harness or connector
- Stop light switch assembly
- Skid control ECU (brake booster with master cylinder assembly)
| Comes on |
- INF Code 231: SAE Code P0572
- Electronically controlled brake system DTC
| | P0573 |
Brake Switch "A" Circuit High |
- | The stop light switch assembly is stuck 10 times or more. |
- Wire harness or connector
- Stop light switch assembly
- Skid control ECU (brake booster with master cylinder assembly)
| Comes on |
- | MONITOR DESCRIPTION
When
the voltage at terminal STP is outside the range of that when the stop
light switch assembly is on or the range of that when the stop light
switch assembly is off for a certain amount of time, the skid control
ECU (brake booster with master cylinder assembly) judges that there is
an open in the stop light switch assembly circuit and illuminates the
MIL and stores a DTC. Also, if the voltage at
terminal STP is always within the range of that when the stop light
switch assembly is on after the vehicle is driven at a certain speed or
more and stopped a specific number of times, the skid control ECU (brake
booster with master cylinder assembly) judges that the stop light
switch assembly is stuck on and illuminates the MIL and stores a DTC. MONITOR STRATEGY |
Related DTCs | P0572: Stop light switch assembly open circuit
P0573: Stop light switch assembly circuit high | |
Required Sensors/Components(Main) | Stop light switch assembly
Speed sensor | | Required Sensors/Components(Related) |
Skid control ECU (brake booster with master cylinder assembly) | |
Frequency of Operation | Continuous | |
Duration | 10 seconds: P0572 10 times: P0573 | |
MIL Operation | Immediately | |
Sequence of Operation | None | TYPICAL ENABLING CONDITIONS All |
Monitor runs whenever the following DTCs are not stored |
None | P0572 |
Both of the following conditions are met | - | |
Serial communication with high side IC | Valid | |
IG1 voltage | Higher than 9.54 V | P0573 |
Serial communication with high side IC | Valid | TYPICAL MALFUNCTION THRESHOLDS P0572 |
Stop light switch assembly voltage | Higher than 2.75 V, and less than 4.25 V | P0573 |
Stop light switch assembly voltage when decelerating vehicle from 30 km/h (19 mph) or more to 3 km/h (2 mph) |
4.25 V or more | COMPONENT OPERATING RANGE P0572 |
All of the following conditions are met | - | |
Stop light switch assembly on experience | On | |
Stop light switch assembly off experience | On | |
Stop light switch assembly voltage | 2.75 V or less, or 4.25 V or more | P0573 |
Both of the following conditions are met |
- | | Serial communication with high side IC |
Valid | | Stop light switch assembly voltage |
2.75 V or less | CONFIRMATION DRIVING PATTERN
- Connect the Techstream to the DLC3.
- Turn the power switch on (IG).
- Turn the Techstream on.
- Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
- Turn the power switch off.
- Turn the power switch on (READY).
- Turn the Techstream on.
- Decelerate the vehicle from a speed of 30 km/h (19 mph) or more to 3 km/h (2 mph) 10 times or more.
- Enter the following menus: Chassis / ABS/VSC/TRAC / Trouble Codes.
- Read the DTCs.
HINT:
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.
- If the DTCs are not output, perform a universal trip and check for permanent DTCs.
Click here 
HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTCs are output, the system is normal.
WIRING DIAGRAM
 CAUTION / NOTICE / HINT
NOTICE:
- After replacing the skid control ECU (brake booster with master cylinder
assembly), perform linear solenoid valve offset learning, ABS holding
solenoid valve learning, yaw rate and acceleration sensor zero point
calibration and system information memorization after performing "Reset
Memory".
Click here
- Inspect the fuses for circuits related to this system before performing the following procedure.
PROCEDURE |
1. | 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 |
| NG |
 | GO TO STEP 5 |
|
OK |
 | |
| 2. |
READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH ASSEMBLY) |
(a) Select the Data List on the Techstream. Click here
Chassis > ABS/VSC/TRAC > Data List
|
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 |
- | Chassis > ABS/VSC/TRAC > Data List
|
Tester Display | | Stop Light SW |
(b) Check that the stop light switch assembly display observed on the Techstream changes according to brake pedal operation.
OK: The Techstream displays on or off according to brake pedal operation.
| NG |
| GO TO STEP 4 |
|
OK | |
| |
(a) Clear the DTCs.
Click here Chassis > ABS/VSC/TRAC > Clear DTCs
(b) Turn the power switch off. (c) Turn the power switch on (READY).
(d) Perform a road test. (e) Check if the same DTC is output. Click here
Chassis > ABS/VSC/TRAC > Trouble Codes
| Result |
Proceed to | | DTCs C1425 and P0573 are not output. |
A | | DTCs C1425 and/or P0573 are output. |
B |
| A |
| USE SIMULATION METHOD TO CHECK |
| B |
| REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY |
| 4. |
CHECK HARNESS AND CONNECTOR (STP TERMINAL) |
| (a) Turn the power switch off. |
 |
|
*a | Front view of wire harness connector
(to Skid Control ECU (Brake Booster with Master Cylinder Assembly)) | | |
(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.
OK: The connector is securely connected. (c) Disconnect the A35 skid control ECU (brake booster with master cylinder assembly) connector.
(d) Check both the connector case and the terminals for deformation and corrosion.
OK: No deformation or corrosion. (e) Measure the voltage according to the value(s) in the table below.
Standard Voltage: |
Tester Connection | Condition |
Specified Condition | |
A35-12 (STP) - Body ground |
Stop light switch assembly on (Brake pedal depressed) |
11 to 14 V | |
A35-12 (STP) - Body ground |
Stop light switch assembly off (Brake pedal released) |
1.5 V or less |
| OK |
| REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY |
| NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT) |
| 5. |
INSPECT STOP LIGHT SWITCH ASSEMBLY | (a) Check the stop light switch assembly.
Click here OK: The stop light switch assembly is normal.
| NG |
| REPLACE STOP LIGHT SWITCH ASSEMBLY |
|
OK | |
| |
| 6. |
CHECK HARNESS AND CONNECTOR (STP TERMINAL) |
| (a) Turn the power switch off. | |
|
|
*a | Front view of wire harness connector
(to Skid Control ECU (Brake Booster with Master Cylinder Assembly)) | | |
(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.
OK: The connector is securely connected. (c) Disconnect the A35 skid control ECU (brake booster with master cylinder assembly) connector.
(d) Check both the connector case and the terminals for deformation and corrosion.
OK: No deformation or corrosion. (e) Measure the voltage according to the value(s) in the table below.
Standard Voltage: |
Tester Connection | Condition |
Specified Condition | |
A35-12 (STP) - Body ground |
Stop light switch assembly on (Brake pedal depressed) |
11 to 14 V | |
A35-12 (STP) - Body ground |
Stop light switch assembly off (Brake pedal released) |
1.5 V or less |
| NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT) |
|
OK | |
| |
(a) Reconnect the A35 skid control ECU (brake booster with master cylinder assembly) connector.
(b) Clear the DTCs. Click here Chassis > ABS/VSC/TRAC > Clear DTCs
(c) Turn the power switch off. (d) Turn the power switch on (READY).
(e) Perform a road test. (f) Check if the same DTC is output. Click here
Chassis > ABS/VSC/TRAC > Trouble Codes
| Result |
Proceed to | | DTCs C1425 and P0573 are not output. |
A | | DTCs C1425 and/or P0573 are output. |
B | HINT: If
the lighting system is normal but the DTC is still output, replace the
skid control ECU (brake booster with master cylinder assembly). Click here
| A | |
USE SIMULATION METHOD TO CHECK |
| B |
| INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT) | | 
