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Fuel Gauge System Test

NOTE: During testing, let the fuel gauge needle stabilize.
  1. Check fuel gauge sending unit. See FUEL GAUGE SENDING UNIT TEST  under COMPONENT TESTING. If sending unit is okay, disconnect electrical connector from fuel gauge sending unit. Turn ignition on. Gauge should indicate empty.
  2. At harness side of sending unit connector, connect a 3.4-watt light bulb between terminals No. 1 and 3. See Fig 1. Gauge should indicate full and light should come on. If gauge indicates as specified, replace sending unit. If gauge does not indicate as specified, remove power source unit. See Figure.
  3. Check for continuity between the following terminals of circuit plate. See Fig 2. If there is no continuity, replace circuit plate. If there is continuity, replace power source unit.
    • "A" and a20.
    • "B" and a19.
    • "C" and a18.
    • "D" and a17.
Fig 1: Testing Fuel Gauge
G93B83940Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 2: Checking Circuit Plate Paths That Lead To Fuel Gauge
G94H46992Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002