Lexus ES: Diagnosis System
DIAGNOSIS SYSTEM
DESCRIPTION
(a) The battery ECU assembly has a self-diagnosis system. If the computer, hybrid control system, or a component is not working properly, the ECU records the conditions that relate to the fault. The ECU also illuminates the master warning light in the combination meter assembly and provides other appropriate messages on the multi-information display, such as the HV system warning message, HV battery warning message, or discharge warning message.
- When troubleshooting OBD II (On-Board Diagnostics) vehicles, the Techstream (complying with SAE J1978) must be connected to the DLC3 (Data Link Connector 3) of the vehicle. Various data in the vehicle ECM (Engine Control Module) can then be read.
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OBD II regulations require that the vehicle's on-board computer illuminates the MIL (Malfunction Indicator Lamp) on the instrument panel when the computer detects a malfunction in:
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- The emission control system components.
- The powertrain control components (which affect vehicle emissions).
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The computer itself.
In addition, the applicable DTCs prescribed by SAE J2012 are recorded in the battery ECU assembly memory. If the malfunction does not recur in 3 consecutive trips, the MIL turns off automatically but the DTCs remain recorded in the battery ECU assembly memory.
- To check for DTCs, connect the Techstream to the DLC3. The Techstream displays DTCs, freeze frame data, and a variety of hybrid control system data. The DTCs and freeze frame data can be cleared with the Techstream. In order to enhance the OBD function on vehicles and develop the off-board diagnosis system, Controller Area Network (CAN) communication is used in this system. CAN is a network which uses a pair of data transmission lines spanning multiple computers and sensors. It allows for high speed communications between the systems and simplification of the wire harness connections.
2 TRIP DETECTION LOGIC
- When a malfunction is first detected, the malfunction is temporarily stored in the battery ECU assembly memory (1st trip). If the same malfunction is detected during the next drive cycle, the MIL is illuminated (2nd trip).
FREEZE FRAME DATA
- The battery ECU assembly records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was moving or stationary, whether the engine was warmed up or not, as well as other data recorded at the time of a malfunction.
AUXILIARY BATTERY VOLTAGE
Standard Voltage:
| Switch Condition | Specified Condition |
|---|---|
| Power switch on (IG) | 11 to 14 V |
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If voltage is below 11 V, replace or recharge the auxiliary battery.
NOTICE:
After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.
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MIL (Malfunction Indicator Lamp)
(a) The MIL is illuminated when the power switch is first turned on (IG), before the READY light comes on.
(b) When the READY indicator turns on, the MIL should turn off. If the MIL remains illuminated, the diagnosis system has detected a malfunction or abnormality in the system.
HINT:
If the MIL is not illuminated when the power switch is first turned on (IG), check the MIL circuit.
for SFI System: Click here
READ NEXT:
Dtc Check / Clear
DTC CHECK / CLEAR CHECK FOR DTCS (a) Connect the Techstream to the DLC3. (b) Turn the power switch on (IG). (c) Turn the Techstream on. (d) Enter the following menus: Powertrain / HV battery / Trouble
Freeze Frame Data
FREEZE FRAME DATA FREEZE FRAME DATA HINT: The battery ECU assembly records vehicle and driving condition information as freeze frame data the moment a DTC is stored. It can be used for estimating or d
Vehicle Behavior Chart
VEHICLE BEHAVIOR CHART VEHICLE BEHAVIOR CHART (a) Vehicle behavior categorized by DTC If a DTC is output, the vehicle behaves as follows. DTC No. Detection Item Vehicle Behavior when DTC is Out
SEE MORE:
Vehicle Control History
VEHICLE CONTROL HISTORY DESCRIPTION
Vehicle Control History is a function that captures and stores ECU data when triggered by specific vehicle behavior.
It may be possible to determine the cause of the malfunction by checking the vehicle history information and freeze frame data.
The number o
Components
COMPONENTS ILLUSTRATION *1 BRAKE MASTER CYLINDER RESERVOIR FILLER CAP ASSEMBLY - - ILLUSTRATION *1 FRONT DISC BRAKE BLEEDER PLUG *2 FRONT DISC BRAKE BLEEDER PLUG CAP *3 REAR DISC BRAKE BLEEDER PLUG *4 REAR DISC BRAKE BLEEDER PLUG CAP Tightening torque for "Maj
