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Home >> Pontiac >> 2007 >> Vibe Standard >> Repair and Diagnosis >> Brakes >> Anti-Lock Brake System, Traction Control System & Stability Control System >> Diagnostic Information and Procedures >> DTC U0073 >> Test Description

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. 7:  Test the CAN - high and CAN - low circuits for an open or high resistance.
  2. 8:  Test the CAN - high and CAN - low circuits for a short between circuits.
DTC U0073

Step Action Value(s) Yes No
Schematic Reference:  Antilock Brake System Schematics  
Connector End View Reference:  Antilock Brake System Connector End Views  
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2
  1. Turn OFF the ignition.
  2. Measure the resistance between the CAN bus terminal - high and CAN bus terminal - low of the data link connector (DLC).
Is the resistance within the specified range?		 54-69 Ω Go to Step 3  Go to Step 4 
3
  1. Turn OFF the ignition.
  2. Measure the resistance between the CAN - low circuit and the BAT terminal of the DLC.
  3. Measure the resistance between the CAN - high circuit and the BAT terminal of the DLC.
Is the resistance as specified?		 1M Ω or Greater Go to Step 5  Go to Step 6 
4 Is the resistance between the CAN bus terminal - high and CAN bus terminal - low of the DLC as specified? Above 69 Ω Go to Step 7  Go to Step 8 
5
  1. Turn OFF the ignition.
  2. Measure the resistance between the CAN - high circuit and the CG terminal of the DLC.
  3. Measure the resistance between the CAN - low circuit and the CG terminal of the DLC.
Is the resistance as specified?		 3k Ω or Greater Go to next U DTC. Go to Diagnostic Trouble Code (DTC) List - Vehicle Go to Step 9 
6
  1. Turn OFF the ignition
  2. Disconnect the electronic brake control module (EBCM) connector.
  3. Measure the resistance between the CAN - high and BAT terminals of the DLC.
  4. Measure the resistance between the CAN - low and BAT terminals of the DLC. Refer to Circuit Testing and Wiring Repairs .
Is the resistance as specified?		 1M Ω or Greater Go to Step 21  Go to Step 10 
7  Test the CAN - high and CAN - low circuits for an open or high resistance.
Did you find and correct the condition?		 - Go to Step 22  Go to Step 11 
8  Test the CAN - high and CAN - low circuits for a short between circuits.
Did you find and correct the condition?		 - Go to Step 22  Go to Step 12 
9
  1. Turn OFF the ignition
  2. Disconnect the EBCM sensor connector.
  3. Measure the resistance between the CAN - high and CG terminals of the DLC.
  4. Measure the resistance between the CAN - low and CG terminals of the DLC. Refer to Circuit Testing and Wiring Repairs .
Is the resistance as specified?		 3k Ω or Greater Go to Step 21  Go to Step 13 
10
  1. Turn OFF the ignition
  2. Connect the EBCM connector.
  3. Disconnect the steering wheel position sensor connector.
  4. Measure the resistance between the CAN - high BAT terminals of the DLC.
  5. Measure the resistance between the CAN - low BAT terminals of the DLC. Refer to Circuit Testing and Wiring Repairs .
Is the resistance as specified?		 1M Ω or Greater Go to Step 19  Go to Step 14 
11 Are DTCs U0073, U0123, U0124, and U0126 all output? - Go to Step 21  Go to Step 19 
12
  1. Turn OFF the ignition
  2. Disconnect the EBCM connector.
  3. Measure the resistance between the CAN bus - high and CAN bus - low terminals of the EBCM. Refer to Circuit Testing and Wiring Repairs .
Is the resistance within the specified range?		 108-132 Ω Go to Step 15  Go to Step 21 
13
  1. Turn OFF the ignition
  2. Connect the EBCM connector.
  3. Disconnect the steering wheel position sensor connector.
  4. Measure the resistance between the CAN - high and CG terminals of the DLC.
  5. Measure the resistance between the CAN - low and CG terminals of the DLC. Refer to Circuit Testing and Wiring Repairs .
Is the resistance as specified?		 3k Ω or Greater Go to Step 19  Go to Step 16 
14
  1. Turn OFF the ignition
  2. Connect the steering wheel position sensor connector.
  3. Disconnect the yaw rate sensor connector.
  4. Measure the resistance between the CAN - high and BAT terminals of the DLC.
  5. Measure the resistance between the CAN - low and BAT terminals of the DLC. Refer to Circuit Testing and Wiring Repairs .
Is the resistance as specified?		 1M Ω or Greater Go to Step 20  Go to Step 17 
15
  1. Turn OFF the ignition
  2. Disconnect the steering wheel position sensor connector.
  3. Measure the resistance between the CAN bus - high and CAN bus - low terminals of the steering wheel position sensor. Refer to Circuit Testing and Wiring Repairs .
Is the resistance within the specified range?		 108-132 Ω Go to Step 20  Go to Step 19 
16
  1. Turn OFF the ignition
  2. Connect the steering wheel position sensor connector.
  3. Disconnect the yaw rate sensor connector.
  4. Measure the resistance between the CAN - high and CG terminals of the DLC.
  5. Measure the resistance between the CAN - low and CG terminals of the DLC. Refer to Circuit Testing and Wiring Repairs .
Is the resistance as specified?		 3k Ω or Greater Go to Step 20  Go to Step 18 
17 Locate and repair the short to B+ in the CAN circuits.
Did you find and correct the condition?		 - Go to Step 22  -
18 Locate and repair the short to ground in the CAN circuits.
Did you find and correct the condition?		 - Go to Step 22  -
19 Replace the steering wheel position sensor. Refer to Steering Wheel Position Sensor Replacement .
Did you complete the replacement?		 - Go to Step 22  -
20 Replace the yaw rate sensor. Refer to Yaw Rate Sensor Replacement .
Did you complete the replacement?		 - Go to Step 22  -
21 Replace the brake pressure modulator valve (BPMV). Refer to Brake Modulator Assembly Replacement (With VSC)  or Brake Modulator Assembly Replacement (Without VSC) .
Did you complete the replacement?		 - Go to Step 22  -
22
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text.
Does the DTC reset?		 - Go to Step 2  System OK
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