Lexus ES: Brake Override System
DESCRIPTION
When the vehicle is being driven with the accelerator pedal depressed, depressing the brake pedal without releasing the accelerator pedal will activate the brake override system to restrict hybrid system output. The conditions for activating the brake override system as well as the items that are controlled are explained below.
Activation Conditions: -
The accelerator pedal and brake pedal are depressed at the same time.
NOTICE:
Brake override control may not be performed depending on the relationship between accelerator opening and vehicle speed.
-
Controls hybrid system output
HINT:
- When the control is operating, requested accelerator torque is controlled in accordance with the brake pedal stroke.
- When the hybrid system output is reduced to a specified level because the accelerator pedal and brake pedal are depressed at the same time, an indicator is displayed on the meter. (Operation of the system can be confirmed when the indicator is displayed on the meter.)
- The accelerator pedal or brake pedal is released.
CAUTION / NOTICE / HINT
Inspection MethodDrive at 10 km/h (6 mph), depress the accelerator pedal by 1/2 to 3/4 and keep it in that position. Under these conditions, if hybrid system output is controlled when the brake pedal is depressed by the left foot of the driver, it can be confirmed that the brake override system has operated.
CAUTION:
Perform this road test only in an appropriate safe location, in accordance with all local laws.
Pay careful attention to the surroundings when performing the road test.
HINT:
The brake override system restricts requested accelerator torque if the brake pedal is depressed when driving with the accelerator pedal depressed. If a customer reports experiencing a loss of power (requested accelerator torque) after the accelerator and brake pedals have both been intentionally depressed, explain that this is not a malfunction, and depressing both the accelerator and brake pedals at the same time should be avoided.
PROCEDURE
| 1. | CHECK DTC OUTPUT (HEALTH CHECK) |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: System Select / Health Check.
(e) Check for DTCs.
| Result | Proceed to |
|---|---|
| No DTCs are output | A |
| DTCs are output | B |
(f) Turn the power switch off.
| B | .gif) | GO TO DTC CHART |
|
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| 2. | READ VALUE USING TECHSTREAM (MASTER CYLINDER CONTROL TORQUE) |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (READY).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Hybrid Control / Data List / Master Cylinder Control Torque.
Powertrain > Hybrid Control > Data List| Tester Display |
|---|
| Master Cylinder Control Torque |
(e) Read the value displayed on the Techstream.
| Result | Proceed to |
|---|---|
| Display changes according to brake pedal depression force | A |
| Other than above | B |
(f) Turn the power switch off.
| B | | CHECK BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY |
|
| 3. | READ VALUE USING TECHSTREAM (ACCELERATOR POSITION SENSOR NO. 1 VOLTAGE %, ACCELERATOR POSITION SENSOR NO. 2 VOLTAGE %) |
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| NG | | REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY |
|
| 4. | READ VALUE USING TECHSTREAM (VEHICLE SPEED) |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (READY).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Hybrid Control / Data List / Vehicle Speed.
Powertrain > Hybrid Control > Data List| Tester Display |
|---|
| Vehicle Speed |
(e) Read the value displayed on the Techstream.
Standard:
| Inspection Condition | Specified Condition |
|---|---|
| Vehicle stopped | 0 km/h (0 mph) |
| Vehicle being driven at a constant speed (16 to 64 km/h (10 to 40 mph)) | No large fluctuations in displayed speed |
CAUTION:
Perform this road test only in an appropriate safe location, in accordance with all local laws.
HINT:
Data can be captured relatively easily by using the snapshot function in the Data List. Confirm the data after performing the drive test.
(f) Turn the power switch off.
| NG | | GO TO METER / GAUGE SYSTEM (SPEED SIGNAL CIRCUIT) |
|
| 5. | READ VALUE USING TECHSTREAM (FR, FL, RR, RL WHEEL SPEED) |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (READY).
(c) Turn the Techstream on.
(d) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List / All Data / FR Wheel Speed, FL Wheel Speed, RR Wheel Speed and RL Wheel Speed.
Chassis > ABS/VSC/TRAC > Data List| Tester Display |
|---|
| FR Wheel Speed |
| FL Wheel Speed |
| RR Wheel Speed |
| RL Wheel Speed |
(e) Read the values displayed on the Techstream.
Standard:
| Inspection Condition | Specified Condition |
|---|---|
| Vehicle stopped | 0 km/h (0 mph) |
| Vehicle being driven at a constant speed (16 to 64 km/h (10 to 40 mph)) | No large fluctuations in displayed speed |
CAUTION:
Perform this road test only in an appropriate safe location, in accordance with all local laws.
HINT:
Data can be captured relatively easily by using the snapshot function in the Data List. Confirm the data after performing the drive test.
(f) Turn the power switch off.
| OK | | END |
| NG | | INSPECT FRONT OR REAR SPEED SENSOR |
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Components
COMPONENTS ILLUSTRATION *1 NO. 2 PARKING BRAKE WIRE ASSEMBLY *2 REAR AXLE HUB BOLT *3 REAR DISC *4 REAR DISC BRAKE CALIPER ASSEMBLY *5 REAR FLEXIBLE HOSE - - Tightening torque for "Major areas involving basic vehicle performance such as moving/turning/stopping":
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