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Home >> Cadillac >> 2007 >> STS Base, 4.6 A, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 139 (Object Detection System) >> Diagnostic Information and Procedures >> Rear Parking Assist Inoperative - Red Indicator Flashes >> Circuit/System Testing >> Diagnostic Indicator Pattern 2, 3, 4 and 5
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Diagnostic Indicator Pattern 2, 3, 4 and 5

WARNING: This page is about a different car, the 2009 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector of the appropriate rear object sensor.
  2. Ignition OFF for 30 seconds, test for less than 5.0 ohms between the low reference circuit terminal 2 and ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the object alarm module.
  3. Ignition ON, transmission in REVERSE, test for 8.0-9.0 volts between the voltage reference circuit terminal 3 and ground.
    • If greater than the specified range, test the voltage reference circuit for a short to voltage. If the circuit tests normal, replace the object alarm module.
    • If less than the specified range, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the object alarm module.
  4. Ignition OFF, disconnect the harness connector at the object alarm module.
  5. Ignition ON, test for less than 1.0 volt between the appropriate signal circuit listed below and ground:
    • LR middle object sensor signal circuit terminal 2
    • LR corner object sensor signal circuit terminal 1
    • RR middle object sensor signal circuit terminal 3
    • RR corner object sensor signal circuit terminal 4
    • If greater than the specified range, test the signal circuit for a short to voltage.
  6. Ignition OFF, test for infinite resistance between the appropriate signal circuit listed below and ground:
    • LR middle object sensor signal circuit terminal 2
    • LR corner object sensor signal circuit terminal 1
    • RR middle object sensor signal circuit terminal 3
    • RR corner object sensor signal circuit terminal 4
    • If not than the specified value, test the signal circuit for a short to ground.
  7. Test for less than 2 ohms between the signal circuit terminal 1 at the sensor harness connector and the appropriate signal circuit listed below:
    • LF middle object sensor signal circuit terminal 2
    • LF corner object sensor signal circuit terminal 1
    • RF middle object sensor signal circuit terminal 3
    • RF corner object sensor signal circuit terminal 4
    • If greater than the specified range, test the signal circuit for an open/high resistance.
  8. If all circuits test normal, test or replace the appropriate rear object alarm sensor.
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