Entry And Start System - How To Proceed With Troubleshooting

Lexus IS250 IS220d GSE20 ALE20 - DOOR LOCK


ENTRY AND START SYSTEM - HOW TO PROCEED WITH TROUBLESHOOTING

  • HINT:
Use the following procedures to troubleshoot the entry and start system.
The intelligent tester can be used in steps 4 and 6.
When troubleshooting the entry and start system using the intelligent tester with the engine switch off, connect the intelligent tester to the vehicle and repeat turning any of the courtesy light switches on and off until communication between the tester and the vehicle begins (the interval ON and OFF should be less than 1.5 sec.).

1.VEHICLE BROUGHT TO WORKSHOP
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2.CUSTOMER PROBLEM ANALYSIS CHECK
  • HINT:
In troubleshooting, confirm that the problem symptoms have been accurately identified. Preconceptions should be discarded in order to make an accurate judgment. To clearly understand what the problem symptoms are, it is extremely important to ask the customer about the problem and the conditions at the time the malfunction occurred.
Gather as much information as possible for reference. Past problems that seem unrelated may also help in some cases.
The following 5 items are important points in the problem analysis
WhatVehicle model, system name
WhenDate, time, occurrence frequency
WhereRoad conditions
Under what conditions?Running conditions, driving conditions, weather conditions
How did it happen?Problem symptoms
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3.INSPECT BATTERY VOLTAGE
  • Standard voltage:
  • 11 to 14 V

If the voltage is below 11 V, recharge or replace the battery before proceeding to the next step.

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4.INSPECT COMMUNICATION FUNCTION OF MULTIPLEX COMMUNICATION SYSTEM (BEAN)

Use the intelligent tester to check if the Multiplex Communication System (MPX) is functioning normally .

  • Result:
  • ResultProceed to
    MPX DTC is not outputA
    MPX DTC is outputB
B.
Go to MULTIPLEX COMMUNICATION SYSTEM
A
5.CHECK FOR DTC

Check for DTCs and note any codes that are output .

Delete the DTCs.

Recheck for DTCs.

  • Result:
  • ResultProceed to
    DTC does not reoccurA
    DTC reoccursB
B.
GO TO DIAGNOSTIC TROUBLE CODE CHART
A
6.PROBLEM SYMPTOMS TABLE
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7.OVERALL ANALYSIS AND TROUBLESHOOTING

On-vehicle inspection

DATA LIST/ACTIVE TEST

Terminals of ECU

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8.REPAIR OR REPLACEMENT
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9.CONFIRMATION TEST
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END