Service Manual — page 140 of 715

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3-50 FUEL SYSTEM (DFI)
Main Throttle Sensor (Service Code 11) (DTC P0120, P0123)

• When   only the service code is available, follow all inspec-
  tion procedures in this section.
• When   the DTC (Diagnostic Trouble Code) is available, fol-
  low inspection procedures that have the DTC in the head-
    line in this section.
   The main throttle sensor is a rotating variable resistor that
change output voltage according to throttle operating. The
ECU senses this voltage change and determines fuel injec-
tion quantity, and ignition timing according to engine rpm,
and throttle opening.
    Input Terminal [A]: BL
    Output Terminal [B]: Y/W
    Ground Terminal [C]: G

Main Throttle Sensor Removal/Adjustment
                            NOTICE
    Do not remove or adjust the main throttle sensor [A]
    since it has been adjusted and set with precision
    at the factory. Never drop the throttle body assy
    especially on a hard surface. Such a shock to the
    main throttle sensor can damage it.

Main Throttle Sensor Inspection (Service Code
11/DTC P0120)
(Checking wire for open circuit)
• Remove:
   Right Side Cover (see Side Cover Removal in the Frame
   chapter)
• Disconnect:
   Main Throttle Sensor Connector
   ECU Connectors (see ECU Removal)
• Check the wiring for continuity between the ECU harness
  connector and sensor connector.
    Wiring Continuity Inspection
     ECU Harness Connector [A] ←→
        Main Throttle Sensor Connector [B]
          Y/W lead (ECU terminal 27) [C]
    If there is no continuity, repair or replace the main har-
    ness.
    If there is continuity, first check the main throttle sensor
    wirings (see Main Throttle Sensor Circuit).
    If there is no continuity, repair or replace the main har-
    ness.
    If there is continuity, second check the terminals of the
    sensor and ECU for corrosion or bent.
    If the terminals are corroded or bent, replace the throttle
    body assy and/or ECU.