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Diagnostic Aids

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Before performing this procedure, ensure that the following conditions are met:

Rear Parking Assist Inoperative - Red Indicator Flashes

Step Action Value(s) Yes No
Schematic Reference:  Rear Parking Assist Schematics  
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 AND POOR CONNECTIONS
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 (Diagnostic Trouble Code (DTC) Displaying  ) 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 (Diagnostic Trouble Code (DTC) Displaying  ) appear as shown in the diagnostic indicator table? - Go to Step 9  Go to Step 5 
5 Does diagnostic indicator pattern #6 (Diagnostic Trouble Code (DTC) Displaying  ) appear as shown in the diagnostic indicator table? - Go to Step 10  Go to Step 6 
6 Does diagnostic indicator pattern #7 (Diagnostic Trouble Code (DTC) Displaying  ) 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 (Diagnostic Trouble Code (DTC) Displaying  ) appear as shown in the diagnostic indicator table? - Go to Step 8  Go to Step 17 
8
  • Turn the ignition OFF.
  • Disconnect only ONE rear object sensor.
  • Perform the following actions after a rear object sensor is disconnected:
    • 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 Diagnostic Trouble Code (DTC) Displaying  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.
  • 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 (Diagnostic Trouble Code (DTC) Displaying ) 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 the 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 .
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 S423 or S424 and the rear object sensor. Refer to CIRCUIT TESTING and to WIRING REPAIRS .
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 .
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 .
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 to WIRING REPAIRS .
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 AND POOR CONNECTIONS and to CONNECTOR REPAIRS .
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 AND POOR CONNECTIONS and to CONNECTOR REPAIRS .
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 AND POOR CONNECTIONS and to CONNECTOR REPAIRS .
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 (Utility)  or Object Alarm Module Replacement (Escalade EXT) .
Did you complete the replacement?		 - Go to Step 22  -
21
IMPORTANT: Program the replacement BCM.
Replace the BCM. Refer to BODY CONTROL MODULE REPLACEMENT .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 
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