Introduction: Diagnosis Lexus ES XV30 facelift

FOR USING OBDII SCAN TOOL OR HAND-HELD TESTER

HINT

1. Before using the scan tools or tester, the scan tool's instruction book or tester's operator manual should be read thoroughly.
2. If the scan tool or tester cannot communicate with the ECU controlled systems when you have connected the cable of the scan tool or tester to the DLC3 with the ignition switch and tester turned ON, there is a problem on the vehicle side or tester side. If the communication is normal when the tester is connected to another vehicle, inspect the diagnosis data link line (Bus(+)line) or ECU power circuit of the vehicle. If the communication is still impossible when the tester is connected to another vehicle, the problem is probably in the tester itself, so perform the Self Test procedures outlined in the Tester Operator's Manual.

HOW TO PROCEED WITH TROUBLESHOOTING

HINT

Carry out a troubleshooting in accordance with the procedure on the following page. Here, only the basic procedure is shown. Details are provided in the Diagnostics information, showing the most effective methods for each circuit. Confirm the troubleshooting procedures first for the relevant circuit before beginning the troubleshooting of that circuit.

1. Vehicle brought to workshop
2. Customer problem analysis Ask the customer about the conditions and environment when the problem occurred.
3. Symptom confirmation and DTC (and freeze frame data) check Check the battery positive voltage. Voltage: 10 - 14 V (Engine stopped) Visually check the wire harness, connectors and fuses for open and short, etc. Warm up the engine to the normal operating temperature. Confirm the problem symptoms and conditions, and check the DTCs according to the applicable chart. OK : Go to step 5 . NG : Go to next step.
4. DTC chart Check the results obtained in step 3 , then confirm the inspection procedure for the system or the part which should be checked using the DTC chart. Go to step 6 .
5. Problem symptoms chart Check the results obtained in step 3 , then confirm the inspection procedure for the system or the part which should be checked using the problem symptoms table.
6. Circuit inspection or parts inspection Confirm the circuit for the system or the part which should be checked using the problem symptoms table or the results obtained in step 4 .
7. Repair Repair the affected system or part in accordance with the instructions in step 6 .
8. Confirmation test After completing repairs, confirm that the problem has been solved. (If the problem dose not reoccur, perform a confirmation test under the same conditions and in the same environment as when it occurred for the first time.) END

SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE

HINT

1. The diagnostic system in LEXUS ES300 has various functions. The first function is the Diagnostic Trouble Code (DTC) Check in which a malfunction in the signal circuits to the ECU is stored in code form in the ECU memory. Another function is the Input Signal Check which checks if the signals from various switches are sent to the ECU correctly. By using these check functions, possible areas of the problem can be narrowed down quickly and troubleshooting can be performed effectively. Diagnostic functions are incorporated in the following systems in LEXUS ES300. SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE System Diagnostic Trouble Code Check Input Signal Check (Sensor Check) Diagnostic Test Mode (Active Test) SFI System X (with Check Mode) X X Electronic Modulated Suspension System X X ABS with EBD System X X X ABS with EBD & BA & TRAC & VSC System X X X Electronic Controlled Automatic Transmission [ECT] X (with Check Mode) X Air Conditioning System X X Supplement Restraint System X Power Window Control System X Power Door Lock Control System X Wireless Door Lock Control System X Engine Immobiliser System X Multiplex Communication System X Cruise Control System X X
2. In the DTC check, it is very important to determine whether the problem indicated by the DTC is still occurring or has occurred in the past but returned to normal at present. In addition, it must be checked in the problem symptom check whether the malfunction indicated by the DTC is directly related to the problem symptom or not. For this reason, the DTC should be checked before and after the symptom confirmation to determine the current conditions. If this is not done, it may, depending on the case, result in an unnecessary troubleshooting for normally operating systems, making it more difficult to detect the problem area, or trying to repair irrelevant areas. Therefore always follow the procedure in the correct order and perform the DTC check.
3. A flow chart showing how to proceed with the troubleshooting using the diagnostic trouble code (DTC) check is shown below. This flow chart shows how to utilize the DTC check effectively. Then, by carefully checking the results, indicates how to proceed either to the DTC troubleshooting or to the troubleshooting of problem symptoms table.

1. DTC check
2. Making a note and clearing of the DTCs displayed
3. Symptom confirmation SYMPTOM CONFIRMATION a Problem symptoms exist b No problem symptoms exist a : Go to step 5 . b : Go to next step.
4. Simulation test using the symptom simulation methods
5. DTC check DTC CHECK a DTC displayed b Normal code displayed a : Troubleshooting of problem indicated by DTC b : Go to next step.
6. Symptom confirmation SYMPTOM CONFIRMATION a No problem symptoms exist b Problem symptoms exist If a DTC is displayed in the initial DTC check, it indicates that a trouble may have occurred in a wire harness or connector in that circuit in the past, therefore check the wire harness and connectors (See «ELECTRONIC CIRCUIT INSPECTION PROCEDURE»(ref-210284-S34294141912005122000000) ). a : System normal b : Troubleshooting of each problem symptom The problem is still occurring in a place other than the diagnostic circuit (The DTC displayed first is either for a past problem or it is a secondary problem).

SYMPTOM SIMULATION

HINT

The most difficult case in troubleshooting is when no problem symptoms occurs. In such cases, a thorough customer problem analysis must be carried out. Then simulate the same or similar conditions and environment in which the problem occurred in the customer's vehicle. No matter how much experience a technician has, or how skilled he may be, if he proceeds to troubleshoot without confirming the problem symptoms, he will tend to overlook something important in the repair operation and make a wrong guess somewhere, which will only lead to a standstill. For example, for a problem which only occurs when the engine is cold, or for a problem which occurs due to vibration caused by the road during driving, etc., the problem can never be determined with the engine hot condition or the vehicle at a standstill. Since vibration, heat or water penetration (moisture) is a likely cause for the problem which is difficult to reproduce, the symptom simulation tests introduced here are effective measures in a point that the external causes are applied to the vehicle in a stationary condition.

Important points in the symptom simulation test

In the symptom simulation test, the problem symptoms should be confirmed, and the problem area or parts must also be found out. To do so, narrow down the possible problem circuits according to the symptoms before starting this test and have a hand-held tester connected beforehand. After that, carry out the symptom simulation test, judging whether the circuit being tested is defective or normal and also confirming the problem symptoms at the same time. Refer to the problem symptoms table of each system to narrow down the possible causes of the symptom.

Scheme 35

Scheme 36

Scheme 37

Scheme 38

1. VIBRATION METHOD: When vibration seems to be the major cause. PART AND SENSOR Apply slight vibration with a finger to the part of the sensor considered to be the problem cause and check that the malfunction occurs. HINT: Applying strong vibration to relays may result in open relays. CONNECTORS Slightly shake the connector vertically and horizontally. WIRE HARNESS Slightly shake the wire harness vertically and horizontally. The connector joint and fulcrum of the vibration are the major areas to be checked thoroughly.
2. HEAT METHOD: When the problem seems to occur when the suspect area is heated. Heat the component that is the possible cause of the malfunction with a hair dryer or similar object. Check if the malfunction occurs. NOTE: Do not heat to more than 60°C (140°F) (Temperature is limited so as not to damage the components). Do not apply heat directly to the parts in the ECU.
3. WATER SPRINKLING METHOD: When the malfunction seems to occur on a rainy day or in a high-humidity condition. Sprinkle water onto the vehicle and check if the malfunction occurs. NOTE: Never sprinkle water directly onto the engine compartment, but indirectly change the temperature and humidity by applying water spray onto the radiator front surface. Never apply water directly onto the electronic components. HINT: If a vehicle is subject to water leakage, the leaked water may contaminate the ECU. When testing a vehicle with a water leakage problem, special caution must be taken.
4. OTHERS: When the malfunction seems to occur when electrical load is excessive. Turn on all the electrical loads including the heater blower, headlights, rear window defogger, etc., and check if the malfunction occurs.

DIAGNOSTIC TROUBLE CODE CHART

The inspection procedure is shown in the table below. This table permits an efficient and accurate troubleshooting using the diagnostic trouble codes displayed in the diagnostic trouble code check. Proceed with troubleshooting in accordance with the inspection procedure given in the diagnostic chart corresponding to the diagnostic trouble codes displayed. The Supplemental Restraint System diagnostic trouble code chart is shown below as an example.

Scheme 39

PROBLEM SYMPTOMS TABLE

The suspected circuits or parts for each problem symptom are shown in the table below. Use this table to troubleshoot the problem when a "Normal" code is displayed in the diagnostic trouble code check but the problem is still occurring. Numbers in the table indicate the inspection order in which the circuits or parts should be checked.

HINT

When the problem is not detected by the diagnostic system even though the problem symptom is present, it is considered that the problem is occurring outside the detection range of the diagnostic system, or that the problem is occurring in a system other than the diagnostic system.

Scheme 40

Scheme 41

Scheme 42

Scheme 43

Scheme 44

Scheme 45

Scheme 46

Scheme 47

Scheme 48

Scheme 49

Scheme 50

Scheme 51

Scheme 52

Scheme 53

1. BASIC INSPECTION RESISTANCE MEASURING CONDITION OF ELECTRONIC PARTS Unless stated, all resistance is measured at an ambient temperature of 20°C (68°F). Because the resistance may be outside the specifications if measured at high temperatures immediately after the vehicle has been running, measurements should be made when the engine has cooled down. HANDLING OF CONNECTOR When removing the connector with a lock, press the connector toward the engagement and remove the lock by making the lock claw movable easily. When removing the connector, do not hold the harness, but hold the connector. Before connecting the connector, check that there are no deformation, damage and missing of the terminals. Connection of the connector with a lock should be securely done until it makes a click sound. In case of checking the connector with a Toyota electrical tester, perform it at the back side (harness side) of the connector using a mini test lead. NOTE: As a water proof connector cannot be checked from its back side, check by connecting the sub-harness. Do not damage the terminals by moving the inserted tester needle. CONNECTOR CHECKING POINTS Checking when the connector is connected: By holding the connector, check the inserted condition and locking efficiency (engaged condition). Checking when the connector is removed: Check the wire harness by pulling lightly (missing terminal, terminal crimping condition, core wire break). Check visually if there is any rust, metal tip, water and bend of terminal (rust, mixing of foreign object, terminal deformation). NOTE: When testing a gold-plated female terminal, always use a gold-plated male terminal. Checking of the contact pressure of the terminal: Prepare the same terminal as a male terminal. By inserting it to a female terminal, check the engaged condition and sliding load. REPAIR METHOD OF CONNECTOR TERMINAL In case that there is any soil at the contact point, clean the contact point using an air gun or shop rag. At this time, never polish the contact point using a sand paper as the platings may come off. In case of abnormal contact pressure, replace the female terminal. At this time, if a male terminal is gold-plated (gold color), use gold-plated female terminals and if it is silver-plated (silver color), use silver-plated female terminals. HANDLING OF WIRE HARNESS In case of removing the wire harness, check the wiring and clamping condition before the work so as to restore it correctly. Never twist, pull or slack off the wire harness more than necessary. Never make the wire harness come into contact with a high-temperature part, rotating, moving, vibrating or acute-angled part (edge of the panel, tip of the screw, etc.). When installing parts, never sandwich the wire harness between them. Never cut or break the cover of the wire harness. If it is cut or broken, replace it or securely repair it with a vinyl tape.
2. CHECK OPEN CIRCUIT For the open circuit in the wire harness in (Scheme 45), perform "(b) Check the continuity" or "(c) Check the voltage" to locate the information. Check the continuity. Disconnect the connectors "A" and "C" and measure the resistance between them. Resistance: 1 ohms or less HINT: Measure the resistance while lightly shaking the wire harness vertically and horizontally. In the case of (Scheme 46): Between terminal 1 of connector "A" and terminal 1 of connector "C" <=> No continuity (open) Between terminal 2 of connector "A" and terminal 2 of connector "C" <=> Continuity Therefore, it is found out that there is an open circuit between terminal 1 of connector "A" and terminal 1 of connector "C". Disconnect the connector "B" and measure the resistance between the connectors. In the case of (Scheme 47): Between terminal 1 of connector "A" and terminal 1 of connector "B1" °Continuity Between terminal 1 of connector "B2" and terminal 1 of connector "C" <=> No continuity (open) Therefore, it is found out that there is an open circuit between terminal 1 of connector "B2" and terminal 1 of connector "C". Check the voltage. In a circuit in which voltage is applied (to the ECU connector terminal), an open circuit can be checked by conducting a voltage check. (Scheme 48), with each connector still connected, measure the voltage between the body ground and terminal 1 of connector "A" at the ECU 5V output terminal, terminal 1 of connector "B", and terminal 1 of connector "C", in that order. If the results are: 5 V: Between terminal 1 of connector "A" and body ground 5 V: Between terminal 1 of connector "B" and body ground 0 V: Between terminal 1 of connector "C" and body ground Then it is found out that there is an open circuit in the wire harness between terminal 1 of "B" and terminal 1 of "C".
3. CHECK SHORT CIRCUIT If the wire harness is ground shorted as in (Scheme 49), locate the information by conducting a "continuity check with the body ground". Check the continuity with the body ground. Disconnect connectors "A" and "C" and measure the resistance between terminal 1 and 2 of connector "A" and the body ground. Resistance: 1 Mohms or higher HINT: Measure the resistance while lightly shaking the wire harness vertically and horizontally. In the case of (Scheme 50): Between terminal 1 of connector "A" and body ground °Continuity (short) Between terminal 2 of connector "A" and body ground <=> No continuity Therefore, it is found out that there is a short circuit between terminal 1 of connector "A" and terminal 1 of connector "C". Disconnect connector "B" and measure the resistance between terminal 1 of connector "A" and body the ground, and terminal 1 of connector "B2" and the body ground. In the case of (Scheme 51): Between terminal 1 of connector "A" and body ground --> No continuity Between terminal 1 of connector "B2" and body ground --> Continuity (short) Therefore, it is found out that there is a short circuit between terminal 1 of connector "B2" and terminal 1 of connector "C".
4. CHECK AND REPLACE ECU NOTE: Start an inspection of the connector from the backside of the connector at the wire harness side with the connector connected to the ECU. When no measuring condition is specified, perform the inspection with the engine stopped and also the ignition switched ON. First check the ECU ground circuit. If it is faulty, repair it. If it is normal, the ECU could be faulty. So, replace the ECU with a normal functioning one and check if the symptoms appear. Measure the resistance between the ECU ground terminal and body ground. Resistance: 1 ohms or less Disconnect the ECU connector, check the ground terminals on the ECU side and wire harness side for bend and check the contact pressure.