Lexus ES: Brake Control Warning Light does not Come ON
DESCRIPTION
The skid control ECU (brake booster with master cylinder assembly) is connected to the combination meter assembly via CAN communication.
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".
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PROCEDURE
| 1. | CHECK CAN COMMUNICATION SYSTEM |
(a) Check if CAN communication system DTCs are output.
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| Result | Proceed to |
|---|---|
| DTCs are not output. | A |
| DTCs are output. | B |
| B |  | INSPECT CAN COMMUNICATION SYSTEM |
|
| 2. | PERFORM ACTIVE TEST USING TECHSTREAM (BRAKE WARNING LIGHT / YELLOW (MINOR MALFUNCTION)) |
(a) Select the Active Test on the Techstream.
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| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| ECB Warning Light | Brake warning light / yellow (minor malfunction) | Warning light ON/OFF |
|
| Tester Display | Measurement Item | Range | Normal Condition | Diagnostic Note |
|---|---|---|---|---|
| ECB Warning Light | Brake warning light / yellow (minor malfunction) | ON or OFF | ON: Warning light on OFF: Warning light off | ECB: Electronically Controlled Brake System |
| Active Test Display |
|---|
| ECB Warning Light |
| Data List Display |
|---|
| ECB Warning Light |
(b) Check the operating condition of the brake warning light / yellow (minor malfunction) when operating it using the Techstream.
| Result | Proceed to |
|---|---|
| Brake warning light / yellow (minor malfunction) in the Data List does not change using the Active Test. | A |
| Brake warning light / yellow (minor malfunction) in the Data List turns ON/OFF using the Active Test. | B |
| A | | REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY |
|
| 3. | INSPECT COMBINATION METER ASSEMBLY |
(a) Perform the Active Test of the combination meter assembly (meter CPU) using the Techstream.
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| Tester Display |
|---|
| ECB Warning |
(b) Check the combination meter assembly.
OK:
The brake warning light / yellow (minor malfunction) turns on or off in accordance with Techstream operation.
| OK | | REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY |
| NG | | INSPECT METER / GAUGE SYSTEM |
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System Diagram
SYSTEM DIAGRAM Communication Table Transmitting ECU Receiving ECU Signal Communication Method Certification ECU (smart key ECU assembly) Main body ECU (multiplex network body ECU) Luggage electrical key switch signal CAN Combination meter assembly Main body ECU (multiplex
