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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2004 🢒 XLR 🢒 Accessories 🢒 Rear Parking Assist 🢒 Rear Parking Assist Inoperative - Red Indicator Flashes

Diagnostic Aids
    • Before performing this procedure, ensure that the vehicle park brake is SET.
    • Remove any snow, mud, ice or road grime that is blocking the sensors.
    • After shorting the diagnostic connector to ground and turning ON the ignition, shift the vehicle into REVERSE within 5 seconds. This will ensure that a reverse input wiring fault is not registered and will result in a misdiagnosis.

Step

Action

Value(s)

Yes

No

Schematic Reference: Rear Parking Assist Schematics

Connector End View Reference: Rear Parking Assist Connector End Views or Computer/Integrating Systems Connector End Views

1

Did you review the operation and perform the necessary inspections?

--

Go to Step 2

Go to Symptoms - Ultrasonic Rear Parking Assist

2
  1. Turn the ignition ON.
  2. Place foot on the brake.
  3. Shift the vehicle into REVERSE.

Does the red indicator continue to flash after the bulb check?

--

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

3
  1. Turn the ignition OFF.
  2. Remove all objects at least 2 meters from the rear bumper.
  3. Enter the diagnostic mode. Refer to Diagnostic Trouble Code (DTC) Displaying for more information.

Does diagnostic indicator pattern #1 appear as shown in the diagnostic indicator table when you enter diagnostics?

--

Go to Step 4

Go to Step 14

4

Does diagnostic indicator pattern #2, #3, #4, or #5 appear as shown in the diagnostic indicator table?

--

Go to Step 9

Go to Step 5

5

Does diagnostic indicator pattern #6 appear as shown in the diagnostic indicator table?

--

Go to Step 10

Go to Step 6

6

Does diagnostic indicator pattern #7 appear as shown in the diagnostic indicator table?

--

Go to Diagnostic Trouble Code (DTC) Displaying and to Diagnostic Trouble Code (DTC) Clearing

Go to Step 7

7

Does diagnostic indicator pattern #8 appear as shown in the diagnostic indicator table?

--

Go to Step 8

Go to Step 17

8
  1. Turn the ignition OFF.
  2. Disconnect only one rear object sensor.
  3. Perform the following actions after a rear object sensor is disconnected:
    4. • Enter the diagnostic mode to determine if the diagnostic indicator pattern #8 will still be displayed. When the sensor causing the short to ground is disconnected, the diagnostic indicator pattern #8 will not be displayed. The diagnostic indicator pattern displayed will be any one of the diagnostic indicator patterns #2, #3, #4 and #5. Refer to LINK for more information on how to enter the diagnostic mode.
    • Reconnect the rear object sensor when it is determined the sensor is not source of the short to ground.
    • Clear the diagnostic trouble code (DTC). Refer to Diagnostic Trouble Code (DTC) Clearing on how to clear the diagnostic trouble codes.
  4. Repeat the above process for all rear object sensors to determine if the sensors are the source of the short to ground.

Does diagnostic indicator pattern #8 still appear as shown in the diagnostic indicator table?

--

Go to Step 15

Go to Step 16

9
  1. Turn the ignition OFF.
  2. Connect the DMM between the signal circuit of the inoperative rear object sensor and the low reference circuit of the rear object sensor at the rear object sensor control module with the harness connected to the module.
  3. Turn the ignition ON.
  4. Place foot on brake.
  5. Shift vehicle into REVERSE.
  6. Measure the voltage between the signal circuit of the inoperative rear object sensor and the low reference circuit of the rear object sensor.

Does the voltage measure greater than the specified value?

7 V

Go to Step 17

Go to Step 11

10
  1. Turn the ignition OFF.
  2. Disconnect the rear object sensor control module connector.
  3. Measure the voltage between the rear parking assist chime signal circuit and a good ground.

Does the voltage measure greater than the specified value?

9.5 V

Go to Step 17

Go to Step 13

11

Test the signal circuit of the inoperative rear object sensor for an open, for a short to ground and for a short to B+. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 12

12

Test the supply voltage circuit and the low reference circuit of the inoperative rear object sensor for an open between S316 or S315 and the rear object sensor. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 16

13

Test the rear parking assist chime signal circuit for an open and for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 18

14

Test the rear parking assist diagnostic circuit for an open and for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 17

15

Test the supply voltage circuit and the low reference circuit of the rear object sensors for an open, for a short to ground and for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 17

16

Inspect for poor connections at the harness connector of the rear object sensor. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 19

17

Inspect for poor connections at the harness connector of the rear object sensor control module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 20

18

Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 21

19

Replace the inoperative rear object sensor. Refer to Rear Object Sensor Replacement .

Did you find and correct the condition?

--

Go to Step 22

--

20

Replace the rear object sensor control module. Refer to Object Alarm Module Replacement .

Did you complete the replacement?

--

Go to Step 22

--

21

Important: Program the replacement BCM.

Replace the BCM. Refer to Body Control Module Replacement in Computer/Integrating Systems.

Did you complete the replacement?

--

Go to Step 22

--

22
  1. Clear all codes. Refer to Diagnostic Trouble Code (DTC) Clearing .
  2. Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2