DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
INSPECT STOP SW FUSE
CHECK STOP LIGHT OPERATION
INSPECT SKID CONTROL ECU (STP1 TERMINAL)
INSPECT SKID CONTROL ECU (IG1 AND GND TERMINAL)
READ VALUE OF INTELLIGENT TESTER (STOP LIGHT SWITCH AND BRAKE PEDAL LOAD SENSING SWITCH)
RECONFIRM DTC
CHECK BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION
RECONFIRM DTC
INSPECT STOP LIGHT SWITCH (POWER SOURCE TERMINAL)
INSPECT STOP LIGHT SWITCH
INSPECT STOP LIGHT CONTROL RELAY
CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ENGINE ROOM NO. 2 RELAY BLOCK)
CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM NO. 2 RELAY BLOCK)
RECONFIRM DTC
CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - STOP LIGHT SWITCH)
RECONFIRM DTC
DTC C1249/49 Open in Stop Light Switch Circuit
DESCRIPTION
The skid control ECU (housed in the actuator assembly) inputs the stop light switch signal and the condition of brake operation.
The skid control ECU has an open detection circuit, which outputs this DTC when detecting an open in the stop light input line while the stop light switch is OFF.
| DTC No. | DTC Detection Condition | Trouble Area |
| C1249/49 | When IG1 terminal voltage is 9.5 to 17.2 V, an open circuit of the stop light switch continues for 0.3 seconds or more.
When the brake pedal load sensing switch is ON, the master cylinder pressure is 2 Mpa or more and the deceleration calculated from the vehicle speed is 0.2 G or more, the stop light switch is OFF for 2 seconds or more.
| STOP SW fuse
Stop light switch
Stop light switch circuit
Stop light control relay (A/T)
Stop light control relay circuit (A/T)
Brake actuator assembly (Skid control ECU)
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WIRING DIAGRAM
INSPECTION PROCEDURE
- When replacing the brake actuator assembly, perform zero point calibration .
Remove the STOP SW fuse from the main body ECU RH.
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
| Tester Connection | Condition | Specified Condition |
| STOP SW (7.5A) fuse | Always | Below 1 Ω |
| 3.INSPECT SKID CONTROL ECU (STP1 TERMINAL) |
Disconnect the skid control ECU connector.
Measure the voltage according to the value(s) in the table below.
- Standard voltage:
| Tester Connection | Condition | Specified Condition |
| A14-27 (STP1) - Body ground | Stop light switch ON (Brake pedal depressed) | 8 to 14 V |
| A14-27 (STP1) - Body ground | Stop light switch OFF (Brake pedal released) | Below 1.5 V |
Depress the brake pedal several times to test the stop light circuit.
Check if the same DTC is recorded .
- Result:
| Condition | Proceed to |
| DTC (C1249/49) is not output | A |
| DTC (C1249/49) is output | B |
- If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step .
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| | REPLACE STOP LIGHT SWITCH |
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| 11.INSPECT STOP LIGHT CONTROL RELAY |
Remove the stop light control relay.
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
| Tester Connection | Condition | Specified Condition |
| 3 - 4 | Always | Below 1 Ω |
| | REPLACE STOP LIGHT CONTROL RELAY |
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| 12.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ENGINE ROOM NO. 2 RELAY BLOCK) |
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
| Tester Connection | Condition | Specified Condition |
| A22-1 - Stop light control relay terminal 4 | Always | Below 1 Ω |
| A22-1 - Body ground | Always | 10 kΩ or higher |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 13.CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM NO. 2 RELAY BLOCK) |
Disconnect the skid control ECU connector.
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
| Tester Connection | Condition | Specified Condition |
| A14-27 (STP1) - Stop light control relay terminal 3 | Always | Below 1 Ω |
| A14-27 (STP1) - Body ground | Always | 10 kΩ or higher |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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Depress the brake pedal several times to test the stop light circuit.
Check if the same DTC is recorded .
- Reinstall the relay, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.
- Result:
| Condition | Proceed to |
| DTC (C1249/49) is not output | A |
| DTC (C1249/49) is output | B |
- If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step .
| | REPLACE BRAKE ACTUATOR ASSEMBLY |
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| A | |
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| INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT) |
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| 15.CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - STOP LIGHT SWITCH) |
Disconnect the skid control ECU connector.
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
| Tester Connection | Condition | Specified Condition |
| A14-27 (STP1) - A22-1 | Always | Below 1 Ω |
| A14-27 (STP1) - Body ground | Always | 10 kΩ or higher |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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|
Reconnect the skid control ECU connector and the stop light switch connector.
Depress the brake pedal several times to test the stop light circuit.
Check if the same DTC is recorded .
- Result:
| Condition | Proceed to |
| DTC (C1249/49) is not output | A |
| DTC (C1249/49) is output | B |
- If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step .
| | REPLACE BRAKE ACTUATOR ASSEMBLY |
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| A | |
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| INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT) |
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LEXUS IS250, IS220d / GSE20 ALE20
