2001 Lexus LS 430FACTORY OEM SERVICE PROCEDURE

Electronically Controlled Transmission (ECT) Pattern Select Switch Circuit

NOTE: If LEXUS scan tool is available, start test from step  1. If this scan tool is not available, start test from step  2.
  1. Using scan tool, check pattern select switch using DATA LIST. If pattern select switch is faulty, go to next step. If pattern select switch is okay, go to next test listed in appropriate SYMPTOM DIAGNOSIS table under TROUBLE SHOOTING .
  2. Check pattern select switch. See PATTERN SELECT SWITCH  under COMPONENT TESTS. Replace pattern select switch as necessary. Retest system operation. If switch is okay, go to next step.
  3. Check circuits for faults between pattern select switch and body control ECU. See WIRING DIAGRAMS . Repair or replace as necessary. If circuits are okay, go to next test listed in BODY NO. 3 CONTROL SYSTEM  table under TROUBLE SHOOTING .
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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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