2004 Lexus LS 430FACTORY OEM SERVICE PROCEDURE

Active Height Control System: Bleeding

WARNING: This page is about a different car, the 2003 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

If any work is done on the AHC system or if air is suspected in the AHC lines, bleed the system of air.

  1. FILL RESERVOIR WITH SUSPENSION FLUID AHCΒ 

    While the vehicle is stopped, pour the suspension fluid AHC in the reservoir tank.

    Fluid: Suspension fluid AHC (08886-01805)Β 

    NOTE: Do not start the engine until the fluid is poured in the reservoir tank.
  2. BLEED AHC FLUID LINESΒ 
    1. Start the engine and push the vehicle height select switch to select the "N" mode.
      NOTE: When the reservoir tank is empty, or after the AHC pump & motor is replaced or removed, starting engine may cause air inflow in the AHC fluid line. In this condition, the AHC system can not be operated even if the fluid is poured into the tank, If this happens, raise the vehicle height of the front or rear wheel by conducting the active test and activate the AHC pump & motor for about 10 seconds. (See PRE-CHECK )
    2. After vehicle height adjustment is completed, check that the AHC pump motor is stopped, then stop the engine.
    3. Connect the hose to the bleeder plug for either right or left damping force control actuator.
    4. Loosen the bleeder plug.
      CAUTION: While the fluid is being discharged, the vehicle height is lowered suddenly.
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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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