2003 Lexus LS 430FACTORY OEM SERVICE PROCEDURE

Hybrid Vehicle Electronic Control Unit Programming

WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Following procedure is for only programming the Hybrid Vehicle Electronic Control Unit (HV ECU) for engine immobilizer system operation when only HV ECU is replaced. Engine immobilizer system may also be referred to as Hybrid Vehicle (HV) immobilizer system. For programming of ignition key and transponder key Electronic Control Unit (ECU) for engine immobilizer system, see appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

If HV ECU is replaced, HV ECU must be programmed for engine immobilizer system operation. To program HV ECU, turn ignition on and leave ignition on for at least 30 minutes and then start the engine. This will allow transponder key ECU to transfer the information to the HV ECU to allow engine immobilizer system operation.

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When to See a Mechanic

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

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

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