On-Vehicle Inspection

INSPECT MAIN BODY ECU (DEFOGGER RELAY)
1. Remove the DEF fuse.
2. Using an ohmmeter, measure the resistance between the terminals of the DEF fuse.
  Standard resistance: Below 1 Ω
3. Install the DEF fuse.
4. Using an ohmmeter, measure the resistance between terminals 4Q-12 and 4Q-4 of the main body ECU connector.
  Standard resistance: Below 1 Ω
5. Turn the ignition switch ON.
6. Turn the defogger switch ON.
7. Using a voltmeter, measure the voltage between terminal 4F-2 of the main body ECU connector and body ground.
  Standard voltage: 11 to 14 V
  
  Fig 1: Inspecting Main Body ECU (Defogger Relay)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002