2003 Lexus ES 300FACTORY OEM SERVICE PROCEDURE

Air Assist System

  1. Ensure engine is at normal operating temperature. Ensure idle speed is 650-750 RPM, transmission is in Neutral and A/C is off. Connect Jumper Wire (09843-18020) between terminals TE1 and E1 of DLC No. 1. See Figure. On ES300, DLC No. 1 is located on front of air intake chamber. On RX300, DLC No. 1 is located on left side of engine compartment, behind fuse box.
  2. On all models, engine speed should increase to about 900-1300 RPM for about 10 seconds, then return to idle (650-750 RPM). Turn ignition off. Disconnect air assist hose from air pipe. See Fig 1. Plug hose end, and cap off hose pipe fitting.
  3. Start engine. If engine idles at about 500 RPM or less (or if engine stalls), air assist system is okay. If engine speed does not operate as specified, check and repair vacuum leak.
Fig 1: Locating Air Assist Hose
G99J51341Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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