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Home >> Cadillac >> 2007 >> STS Base, 4.6 A, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 236 (Object Detection System) >> Diagnostic Information and Procedures >> Rear Parking Assist Inoperative - Red Indicator Flashes >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2010 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.

Diagnostic Indicator Pattern 1

  1. Enter the diagnostic mode. Refer to Diagnostic Trouble Code (DTC) Displaying . Verify that the Diagnostic Indicator Pattern 1 is displayed as shown in the diagnostic indicator list.
    • If the Diagnostic Indicator Pattern 1 does not display after entering the diagnostic mode, test the signal circuit terminal 16 for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the rear object sensor control module.
  2. Proceed to the next Diagnostic Indicator Pattern displayed.

Diagnostic Indicator Pattern 2, 3, 4 and 5

  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 rear object sensor 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 rear object sensor 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 rear object sensor module.
  4. Ignition OFF, disconnect the harness connector at the rear object sensor 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.

Diagnostic Indicator Pattern 6

  1. Ignition OFF, disconnect the harness connector at the rear object sensor control module.
  2. Ignition ON, test for 9.5 volts between the chime control circuit terminal 22 and ground.
    • If less than the specified value, test the chime control circuit for a short to ground or an open/high resistance. If all circuits test normal, replace the BCM.
    • If greater than the specified value, refer to Speaker Malfunction .

Diagnostic Indicator Pattern 7 

IMPORTANT: When entering the diagnostic mode, it is necessary to follow the instructions as indicated. Refer to Diagnostic Trouble Code (DTC) Displaying . If the vehicle is not shifted into reverse within 5 seconds after turning the ignition ON, the diagnostic mode will still be initiated but a reverse input wiring fault will be registered as Diagnostic Indicator Pattern 7 as shown in the indicator list.

Verify that the Diagnostic Indicator Pattern 7 displays as shown in diagnostic indicator list.

Diagnostic Indicator Pattern 8 and 9 

    IMPORTANT: Diagnostic indicator patterns 8 or 9 are displayed in sequence of diagnostic indicator patterns 2, 3, 4 and 5.
  1. While still in the diagnostic mode, disconnect the rear object sensors one at a time and verify that the indicator pattern 8 or 9 does not display after the suspect sensors has been disconnected.
    • If the indicator pattern 8 or 9 continues to display after each sensor has been disconnected and reconnected, test the object sensor supply voltage circuit and the low reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear object sensor control module.
    • If the indicator pattern 8 and 9 does not display after disconnecting the suspect sensor, replace the suspect sensor.
  2. If all circuits test normal, replace the rear object sensor control module.
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