Service Manual — page 191 of 715

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FUEL SYSTEM (DFI) 3-101
Oxygen Sensor Heater (Service Code 67) (DTC P0030)
Oxygen Sensor Heater Removal/Installation
  The oxygen sensor heater is built in the oxygen sensor.
So, the heater itself can not be removed. Remove the oxy-
gen sensor (see Oxygen Sensor Removal in the Electrical
System chapter).
Oxygen Sensor Heater Resistance Inspection
• Turn the ignition switch off.
• connector
  Open  the clamp [A], and pull out the oxygen sensor lead
             [B].
• Disconnect the oxygen sensor lead connector.

• Connect  a digital meter [A] to the oxygen sensor lead con-
  nector [B].
• Measure the oxygen sensor heater resistance.
  Oxygen Sensor Heater Resistance
    Connections: BK lead [C] ←→ BK lead [D]
    Standard: 11.7 ∼ 14.5 Ω @20° C (68°F)
  If the reading is out of the standard, replace the sensor.
  If the reading is within the standard, check the power
  source voltage (see Oxygen Sensor Heater Power
  Source Voltage Inspection).
Oxygen Sensor Heater Power Source Voltage
Inspection
• Turn  the ignition switch off.
• nect the measuring
  Disconnect   the oxygen sensor lead connector and con-
                       adapter [A] between the connectors.
   Main Harness [B]
   Oxygen Sensor [C]
  Special Tool - Measuring Adapter: 57001-1700
• Connect a digital meter [D] to the measuring adapter lead.
  Oxygen Sensor Power Source Voltage
    Connections to Adapter:
      Digital Meter (+) → R (main harness BR/W) lead
      Digital Meter (–) → Frame Ground Terminal

• Measure    the power source voltage with the engine
  stopped and with the connector joined.
• Turn the ignition switch on.
  Power Source Voltage
    Standard: Battery Voltage

• Turn  the ignition switch off.
  If the reading is out of the standard, check the following
  for open circuit.
   ECU Fuse 15 A (see Fuse Inspection in the Electrical
   System chapter)
   Power Source Wiring (see Oxygen Sensor Circuit)