LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2002 >> ES 300 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Idle Air Control (IAC) System >> System Operation
April 5, 2026: LEMON Manuals is launched! Read the announcement.

System Operation

  1. Ensure engine is at normal operating temperature. Ensure idle speed is 650-750 RPM. Ensure transmission is in Neutral. Turn A/C off. Connect Fused Jumper Wire (09843-18020) between terminals TE1 and E1 of DLC No. 1. See Fig 1. 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 1000 RPM for about 5 seconds then return to idle (650-750 RPM). If engine speed is as specified, go to AIR ASSIST SYSTEM . If engine speed is not as specified, disconnect jumper wire from DLC No. 1. Check IAC valve operation. Replace IAC valve as necessary. See IAC VALVE OPERATION . If IAC valve is okay, check for open or short in IAC valve wiring. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace ECM.
Fig 1: Identifying Data link Connector (DLC) No. 1 Connector Terminals
G97E06179Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
scientia non olet · About LEMON Manuals