On-Vehicle Inspection

WARNING: This page is about a different car, the 2008 Scion xB. However, it is still accessible from the selected car via links, so may be relevant.

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: Identifying DEF Fuse
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002