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Home >> Cadillac >> 2015 >> CTS V, Automatic Trans >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Instrument Panel System Displays And Gauges (Coupe) >> Diagnostic Information and Procedures >> Fuel Gauge Inaccurate or Inoperative >> Circuit/System Testing

Circuit/System Testing

NOTE:
  • Circuit/System Verification must be performed before proceeding with Circuit/System Testing.
  • If equipped, the following tests can be performed at an inline connector. See schematics for the corresponding terminals to test at.
  1. Ignition OFF, disconnect the harness connector at the B46A primary and B46B secondary fuel level sensor.
  2. Ignition OFF for 60 seconds, test for less than 5 Ω between the low reference circuit terminals listed below and ground.
    • Primary terminal 1
    • Secondary terminal A
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Ignition ON, test for 4.8-5.2 V between the signal circuit terminals listed below and ground.
    • Primary terminal 1
    • Secondary terminal A
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Install a jumper wire between the signal circuit terminal 1 and A.
  5. Install the Instrument Panel Tester between the jumped signal circuits and the low reference circuit. Verify the Instrument Panel Tester resistance is set at 40-250 Ω before turning the ignition ON.
    • If not displaying the specified range, test both signal circuits for an open/high resistance. If the circuits test normal, replace the ECM.
  6. Ignition ON, verify that the scan tool Fuel Tank Level Remaining parameter varies between 5 and 95 percent as the Instrument Panel Tester resistance is varied between 40 and 250 Ω.
    • If not within the specified range, replace the K20 ECM.
  7. While varying the Instrument Panel Tester resistance between 40 and 250 Ω verify the fuel gauge moves between empty and full.
    • If not within the specified range, replace the fuel gauge.
  8. If all circuits test normal, perform the fuel level sensor component test before replacing the appropriate fuel level sensor.
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