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Home >> Lexus >> 1997 >> LX 450 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Circuit Tests >> DTC P0110: Intake Air Temperature (IAT) Sensor Circuit >> Diagnosis & Repair

Diagnosis & Repair

  1. Connect scan tool to DLC No. 3 connector. See Figure. Turn ignition on. Using scan tool, monitor IAT sensor temperature. If temperature displayed is same as outside temperature, check component and ECM connections. Problem is intermittent.
  2. If temperature displayed is 284°F (140°C), go to step 5). If temperature displayed is -40°F (-40°C), turn ignition off. Disconnect MAF sensor connector. Using jumper wire, connect MAF wiring harness connector terminals No. 3 and 4. See Figure. Turn ignition on. Using scan tool, monitor IAT sensor temperature.
  3. If temperature displayed is 284°F (140°C) or more, replace MAF sensor and retest. If temperature displayed is less than 284°F (140°C), turn ignition off. Remove jumper wire. Access ECM behind right instrument panel speaker. Connect jumper wire between terminals No. 3 (Blue/Yellow wire) and No. 9 (Brown/Black wire) at ECM E5 connector. See Figure.
  4. If temperature displayed on scan tool is 284°F (140°C) or more, check and repair circuits between MAF wiring harness connector and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed on scan tool is less than 284°F (140°C), replace ECM and retest.
  5. Turn ignition off. Disconnect MAF sensor connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace MAF sensor and retest. If temperature displayed is not -40°F (-40°C), turn ignition off.
  6. Access ECM behind right instrument panel speaker. Disconnect ECM E5 connector. See Figure. Turn ignition on. If temperature displayed is -40°F (-40°C), locate and repair short circuit in wiring harness between MAF sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed by scan tool is not -40°F (-40°C), replace ECM and retest.
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