2012 Lexus IS 350 Base, AWDFACTORY OEM SERVICE PROCEDURE

Problem Symptoms Table

HINT: 

  • Use the table below to help determine the cause of the problem symptom. The potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
  • Inspect the fuses and relays related to the system before inspecting the suspected areas below.
SMART ACCESS SYSTEM WITH PUSH-BUTTON START

Symptom Suspected Area Refer to
Power does not turn on (neither ACC nor IG is possible). 1. AM2 Fuse Refer to Power Source Mode does not Change to ON (IG and ACC)
2. Engine Switch Refer to Power Source Mode does not Change to ON (IG and ACC)
3. Cowl Side J/B RH Refer to Power Source Mode does not Change to ON (IG and ACC)
4. Cowl Side J/B LH Refer to Power Source Mode does not Change to ON (IG and ACC)
5. IG2 Relay Refer to Power Source Mode does not Change to ON (IG and ACC)
6. Wire Harness or Connector Refer to DESCRIPTION
7. Power Source Control ECU Refer to Power Source Mode does not Change to ON (IG and ACC)
Power is not turned on (only ACC is not turned on). 1. AM2 Fuse Refer to Power Source Mode does not Change to ON (ACC)
2. Cowl Side J/B RH Refer to Power Source Mode does not Change to ON (ACC)
3. Wire Harness or Connector Refer to Power Source Mode does not Change to ON (ACC)
4. Power Source Control ECU Refer to Power Source Mode does not Change to ON (ACC)
Power is not turned on (only IG is not turned on). 1. AM2 Fuse Refer to Power Source Mode does not Change to ON (IG)
2. Cowl Side J/B RH Refer to Power Source Mode does not Change to ON (IG)
3. Cowl Side J/B LH Refer to Power Source Mode does not Change to ON (IG)
4. IG2 Relay Refer to Power Source Mode does not Change to ON (IG)
5. Wire Harness or Connector Refer to Power Source Mode does not Change to ON (IG)
6. Power Source Control ECU Refer to Power Source Mode does not Change to ON (IG)
Engine does not start. 1. Power Source Control ECU Refer to Engine does not Start
2. Certification ECU Refer to Engine does not Start
3. Shift Lock Control ECU Refer to Engine does not Start
4. ID Code Box Refer to Engine does not Start
5. Stop SW Fuse Refer to Engine does not Start
6. Stop Light Switch Refer to Engine does not Start
7. Electrical Steering Lock Function Refer to Engine does not Start
8. SFI System Refer to Engine does not Start
9. Engine Immobiliser System Refer to Engine does not Start
10. Wire Harness or Connector Refer to Engine does not Start
Engine switch indicator light does not come on. Engine switch indicator light circuit Refer to Engine Switch Indicator Circuit
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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