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Home >> Lexus >> 2004 >> IS 300 Base, Automatic >> Repair and Diagnosis (Single Page) >> External Pages >> Different car >> Section 17 (Engine Controls - System & Component Testing) >> Relays & Solenoids >> Relays >> Air/Fuel (A/F) HTR Relay, Circuit Opening Relay, EFI Main Relay Or Starter Relay
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Air/Fuel (A/F) HTR Relay, Circuit Opening Relay, EFI Main Relay Or Starter Relay

WARNING: This page is about a different car, the 2002 Lexus RX 300 and 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Remove relay to be tested. On RX300, circuit opening relay may be located in fuse/relay box on left side of engine compartment or relay box under left side of instrument panel. On ES300, circuit opening relay is located in fuse/relay box on left side of engine compartment. On all models, A/F HTR relay, EFI main relay and starter relay are located in the main fuse/relay box on left side of engine compartment.
  2. Check for continuity between relay terminals No. 1 and 2. See Fig 1 or Fig 2 . Continuity should exist. Check for continuity between relay terminals No. 3 and 5. Continuity should not exist.
  3. Using jumper wires, apply battery voltage across relay terminals No. 1 and 2. Check for continuity between relay terminals No. 3 and 5 with relay energized. Continuity should exist. If continuity is not as specified, replace relay.
Fig 1: Identifying Starter Relay Terminals
G93H79589Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 2: Identifying A/F HTR Relay, Circuit Opening Relay & EFI Main Relay Terminals
G97A06177Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002