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Home >> Cadillac >> 2003 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 459 (Antilock Brake System, Traction Control System & Stability Control System) >> Diagnostic Information and Procedures >> DTC C0131: Master Cylinder Pressure Sensor Circuit >> Test Description
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Test Description

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The number below refers to the step number on the diagnostic table.

  1. 3:  This step is required for vehicles equipped with a hydro-boost brake assist system only. If the vehicle being serviced has vacuum assisted brakes, proceed to step 4.
DTC C0131

Step Action Yes No
IMPORTANT: Use the scan tool to read both current and history DTCs before proceeding. If DTC C0292 is set, diagnose that DTC before proceeding with diagnostics for C0131.
If DTC C0161 is set, diagnose that DTC before proceeding with diagnostics for C0131.
Schematic Reference:  ABS Schematics  
1 Did you perform the ABS Diagnostic System Check? Go to Step 2  Go to Diagnostic System Check - ABS (W/O JL4)  or Diagnostic System Check - ABS (W/JL4) 
2 Inspect the vehicle for the following and ensure that there is no base brake failure.
  • Dragging brakes
  • Faulty parking brake switch
  • Brake fluid leakage
  • Air in hydraulic system
  • Seized brake calipers
  • Swollen, kinked or otherwise damaged brake hoses

Did you find and correct the condition?		 Go to Step 9  Go to Step 3 
3  Drive the vehicle in order to verify that the brakes do not self-apply during turning maneuvers.
Do the brakes self-apply during turning maneuvers?		 Go to Symptoms - Hydraulic Brakes in Hydraulic Brakes Go to Step 4 
4
  1. Use the scan tool to clear the DTCs.
  2. Turn OFF the ignition for 5 seconds.
  3. Turn ON the ignition.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?		 Go to Step 5  Go to Diagnostic Aids
5
  1. Select the VSES Data Display function on the scan tool.
  2. Observe the Brake Switch Status parameter while pressing and releasing the brake pedal.
Does the Brake Switch Status change while pressing and releasing the brake?		 Go to Step 6  Go to DTC C0161 
6
  1. Remove the EBCM from the vehicle. Refer to Electronic Brake Control Module Replacement (w/ JL4)  or Electronic Brake Control Module Replacement (w/o JL4) .
  2. Inspect the master cylinder pressure sensor connector within the EBCM for damage or corrosion.
Is there connector damage or corrosion present?		 Go to Step 7  Go to Step 8 
7
IMPORTANT: Following EBCM replacement, perform the set-up procedure for the EBCM and perform the Yaw Rate Reference Table Reset Procedure. Use the scan tool to perform the Tire Size Calibration procedure.
Replace the EBCM. Refer to Electronic Brake Control Module Replacement (w/ JL4)  or Electronic Brake Control Module Replacement (w/o JL4) .Did you complete the replacement?		 Go to Step 9  -
8
IMPORTANT: Following EBCM replacement, perform the set-up procedure for the EBCM and perform the Yaw Rate Reference Table Reset Procedure. Use the scan tool to perform the Tire Size Calibration procedure.
Replace the EBCM and the BPMV. Refer to Electronic Brake Control Module Replacement (w/ JL4)  or Electronic Brake Control Module Replacement (w/o JL4)  and Brake Pressure Modulator Valve (BPMV) Replacement (w/ JL4)  or Brake Pressure Modulator Valve (BPMV) Replacement (w/o JL4) .Did you complete the replacements?		 Go to Step 9  -
9
  1. Use the scan tool Clear All Class 2 DTCs function to clear all of the DTCs from all modules.
  2. Turn OFF the ignition for 5 seconds.
  3. Turn ON the ignition.
  4. 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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