Lexus ES: Diagnosis System
DIAGNOSIS SYSTEM
DESCRIPTION
When troubleshooting a vehicle with a diagnosis system, the only difference from the usual troubleshooting procedure is connecting the Techstream to the vehicle and reading various data output from the skid control ECU (brake booster with master cylinder assembly).
The skid control ECU (brake booster with master cylinder assembly) records DTCs when it detects a malfunction in itself or in its circuits.
To check for DTCs, connect the Techstream to the DLC3 on the vehicle. The Techstream can be used to clear the DTCs, activate various actuators, and check the Freeze Frame Data and Data List.
(a) Check the auxiliary battery voltage.
Standard Voltage:
11 to 14 V
If the voltage is below 11 V, recharge the auxiliary battery before proceeding to the next step.
(b) Check the DLC3.
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DIAGNOSIS
(a) If the skid control ECU (brake booster with master cylinder assembly) detects a malfunction, the ABS warning, brake warning / red (malfunction), brake warning / yellow (minor malfunction) and slip indicator lights will come on in order to warn the driver. Also, if the vehicle is under the following conditions and the brake hold switch (No. 3 combination switch assembly) is turned on, the brake hold operated indicator light blinks.
-
Vehicle Conditions:
- The driver side door is closed.
- The driver side seat belt is fastened.
(b) DTCs are simultaneously stored in memory.
The DTCs can be read by connecting the Techstream.
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(c) This system has a Test Mode (Signal Check) function.
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DTC FOR RELATED SYSTEM MALFUNCTION
(a) When the skid control ECU (brake booster with master cylinder assembly) detects DTCs stored by related systems, it stores DTCs to indicate the malfunctioning system.
DTC for Related System Malfunction| Malfunctioning System | Output DTC | DTC Storage | System/Control Condition |
|---|---|---|---|
| Hybrid control system | DTC C1310 (INF code 1140) | Current and history DTCs are cleared when the system returns to normal. | VSC system is disabled |
| DTC C1310 (INF code 1141) | Brake hold control operation is prohibited | ||
| Electric parking brake system | DTC C13AF DTC U0128 | Current DTCs are cleared when the system returns to normal. | Brake hold control operation is prohibited |
| Airbag system | DTC C147D DTC U0151 | Current DTCs are cleared when the system returns to normal. | Secondary collision brake control operation is prohibited |
HINT:
The above DTCs may be stored in the skid control ECU (brake booster with master cylinder assembly) even if it was never stored as a history DTC or cleared in the system that caused the DTC to be stored.
WARNING LIGHT AND INDICATOR LIGHT INITIAL CHECK
(a) When the power switch is turned on (IG), check that the ABS warning, brake warning / red (malfunction), brake warning / yellow (minor malfunction), VSC OFF indicator, slip indicator, brake hold standby indicator and brake hold operated indicator lights all come on for approximately 3 seconds.
HINT:
- When the brake fluid level is low, the brake warning light / red (malfunction) comes on.
- If the warning light and indicator light check results are not normal, proceed to troubleshooting for the ABS warning, brake warning / red (malfunction), brake warning / yellow (minor malfunction), VSC OFF indicator, slip indicator, brake hold standby indicator and brake hold operated indicator light circuits.
- If an indicator remains on or does not come on, proceed to troubleshooting for the light circuits listed below.
| Trouble Area | See Procedure |
|---|---|
| ABS warning light circuit (Remains on) | |
| ABS warning light circuit (Does not come on) | |
| Brake warning light / red (malfunction) circuit (Remains on) | |
| Brake warning light / red (malfunction) circuit (Does not come on) | |
| Brake warning light / yellow (minor malfunction) circuit (Remains on) | |
| Brake warning light / yellow (minor malfunction) circuit (Does not come on) | |
| VSC OFF indicator light circuit (Remains on) | |
| VSC OFF indicator light circuit (Does not come on) | |
| Slip indicator light circuit (Remains on) | |
| Slip indicator light circuit (Does not come on) | |
| Brake hold standby indicator light circuit | |
| Brake hold operated indicator light circuit | |
READ NEXT:
Diagnostic Trouble Code Chart
DIAGNOSTIC TROUBLE CODE CHART Electronically Controlled Brake System DTC No. Detection Item INF Code MIL Note Link C1202 Master Reservoir Level Malfunction 1126 Comes on
IN
Dtc Check / Clear
DTC CHECK / CLEAR HINT:
DTCs which are stored in the skid control ECU (brake booster with master cylinder assembly) can be displayed on the Techstream. The Techstream can display the current, pendi
Excessive Brake Pedal Travel (No Fluid Leaks and No Air in System)
DESCRIPTION Depending on the malfunction, the skid control ECU (brake booster with master cylinder assembly) prohibits operation of the electronically controlled brake system to protect components and
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On-vehicle Inspection
ON-VEHICLE INSPECTION PROCEDURE 1. INSPECT THROTTLE BODY WITH MOTOR ASSEMBLY (a) Before cleaning, or after cleaning the throttle body with motor assembly and installing it to the vehicle, turn the engine switch on (IG) without operating the accelerator pedal sensor assembly. NOTICE: If the accelerat
Cooling Fan Circuit
DESCRIPTION The ECM calculates an appropriate cooling fan speed based on the engine coolant temperature, air conditioning switch status, refrigerant pressure, engine speed and vehicle speed, and sends a signal to the cooling fan ECU (fan with motor assembly). The cooling fan ECU (fan with motor asse
