Air Assist System: Tacoma

2004 Toyota Matrix XR, FWD, StandardSECTION Tacoma
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2003 Toyota Tundra, 2003 Toyota Tacoma, 2003 Toyota Sienna, 2003 Toyota Sequoia, and 2003 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
  1. Start engine. Warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS - V6 & V8 article.
  2. Turn ignition off. Apply parking brake and place transmission/transaxle in Neutral. Ensure A/C is off.
  3. Note location of data link connector No. 3 at driver's side of instrument panel. See Figure. Install Jumper Wire (SST 09843-18040) between terminals No. 4 (CG) and 13 (TC) on data link connector No. 3. See Figure. Go to next step.
  4. Start engine and note engine speed. After engine speed is kept at 900-1300 RPM for 10 seconds, ensure engine returns to idle speed. Turn ignition off.
  5. Disconnect air assist hose from IAC valve. See Fig 1. Place plug on end of air assist hose. Go to next step.
  6. Start engine and note idle speed. Idle speed should be 500 RPM or less which may cause the engine to stall. Turn ignition off. If idle speed is not 500 RPM or less, check for air leak between air assist hoses, air pipe and fuel injectors. Remove plug and jumper wire. Reconnect air assist hose.
Fig 1: Disconnecting Air Assist Hose (Tacoma)
G98J11519Courtesy of Β© TOYOTA, LICENSE AGREEMENT TMS1002
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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.