On-Vehicle Inspection

REMOVE RELAY BLOCK COVER
REMOVE A/F SENSOR HEATER RELAY
INSPECT A/F SENSOR HEATER RELAY CONTINUITY
1. Using an ohmmeter, check that there is continuity between terminals 1 and 2.
  If there is no continuity, replace the relay.
2. Check that there is no continuity between terminals 3 and 5.
  If there is continuity, replace the relay.
  
  Fig 1: Checking A/F Sensor Heater Relay Continuity Between Terminals 1 And 2
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT A/F SENSOR HEATER RELAY OPERATION
1. Apply battery voltage across terminals 1 and 2.
2. Using an ohmmeter, check that there is continuity between terminals 3 and 5.
  If there is no continuity, replace the relay.
REINSTALL A/F SENSOR HEATER RELAY
REINSTALL RELAY BLOCK COVER

Fig 2: Checking A/F Sensor Heater Relay Continuity Between Terminals 3 And 5
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002