- Stop light switch
- Stop light switch circuit
- ECM
| Last Modified: 11-29-2007 | 1.6 C | |
| Service Category: Engine/Hybrid System | Section: Cruise Control | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM000000ZRE02TX |
| Title: CRUISE CONTROL: DYNAMIC LASER CRUISE CONTROL SYSTEM: DESCRIPTION (2008 Sequoia) | ||
|
DTC |
P0571 |
Brake Switch "A" Circuit |
DESCRIPTION
When the brake pedal is depressed, the stop light switch sends a signal to the ECM. When the ECM receives this signal, it cancels the cruise control. The fail-safe function operates to enable normal driving even if there is a malfunction in the stop light signal circuit. The cancellation condition occurs when voltage is applied to terminal STP. When the brake is applied, voltage is normally applied to terminal STP of the ECM through the STOP fuse and the stop light switch, and the ECM turns the cruise control off.
|
DTC No. |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
P0571 |
Voltage of STP terminal and that of ST1- terminal of ECM are less than 1 V for 0.5 seconds. or more. |
|
|
This trouble code is output when the BRK relay error signal from the skid control ECU for 0.2 seconds. or more while the dynamic cruise control is in operation. |
VSC system |
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
|
1. |
CHECK FOR DTC (IN VEHICLE STABILITY CONTROL SYSTEM) |
(a) Check for DTCs in Vehicle Stability Control System
.
OK:
DTC is not output.
|
|
2. |
READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH) |
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Cruise Control / Data List.
(e) Check the Data List for proper functioning of the cruise control main switch.
ECM (Laser Cruise)
|
Tester Display |
Measurement Item/Range |
Normal Condition |
Diagnostic Note |
|---|---|---|---|
|
Stop Light SW M-CPU |
Stop light switch signal (Main CPU) / ON or OFF |
ON: Brake pedal depressed OFF: Brake pedal released |
- |
OK:
Normal conditions listed above are displayed.
Result
|
Result |
Proceed to |
|---|---|
|
NG |
A |
|
OK (for 2UZ-FE) |
B |
|
OK (for 3UR-FE) |
C |
|
|
3. |
CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - BATTERY) |
|
(a) Disconnect the A4 connector from the stop light switch. |
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Switch Condition |
Specified Condition |
|---|---|---|
|
A4-2 - Body ground |
Always |
11 to 14 V |
|
A4-3 - Body ground |
Ignition switch ON |
11 to 14 V |
(c) Reconnect the stop light switch connector.
|
|
4. |
INSPECT STOP LIGHT SWITCH |
|
(a) Remove the stop light switch
|
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Switch Condition |
Specified Condition |
|---|---|---|
|
1 - 2 |
Switch pin not pushed |
Below 1 Ω |
|
3 - 4 |
Switch pin not pushed |
10 kΩ or higher |
|
1 - 2 |
Switch pin pushed |
10 kΩ or higher |
|
3 - 4 |
Switch pin pushed |
Below 1 Ω |
(c) Reinstall the stop light switch.
|
|
5. |
INSPECT ECM |
|
(a) Disconnect the A27 connector from the ECM. |
(b) Turn the ignition switch to ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
A27-26 (STP) - Body ground |
Brake pedal is depressed |
11 to 14 V |
|
A27-26 (STP) - Body ground |
Brake pedal is released |
Below 1 V |
|
A27-35 (ST1-) - Body ground |
Brake pedal is depressed |
Below 1 V |
|
A27-35 (ST1-) - Body ground |
Brake pedal is released |
11 to 14 V |
Result
|
Result |
Proceed to |
|---|---|
|
NG |
A |
|
OK (for 2UZ-FE) |
B |
|
OFF (for 3UR-FE) |
C |
(d) Reconnect the ECM connector.
|
|
|