GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2002 🢒 Yukon XL - 2WD 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C0201-C0204

Circuit Description

The EBCM uses the input from the master cylinder pressure sensor for more accurate braking control during a vehicle stability enhancement system (VSES) event. The master cylinder pressure is directly proportional to the amount of force that is applied to the brake pedal.

Conditions for Running the DTC

C0201, C0202, C0203

The ignition is ON.

C0204

The vehicle is decelerating with the master cylinder pressure greater than 1400 kPa (200 psi) and all of the following are true:

    • The vehicle is driven relatively straight forward at a speed greater than 19 km/h (12 mph).
    • The throttle position is less than 5 percent.
    • The vehicle is in DRIVE.
    • The parking brake is released.

Conditions for Setting the DTC

C0201

The master cylinder pressure sensor circuitry is detected as open or shorted for 200 milliseconds.

C0202

The master cylinder pressure sensor signal indicates a sudden change in the master cylinder pressure which exceeds a physical limitation.

C0203

Either of the following conditions may cause DTC C0203 to set:

    • The zero-pressure signal voltage is detected as being out of range by at least 0.25 volts.
    • The brake switch is closed and the master cylinder pressure is greater than 862 kPa (125 psi) for 500 milliseconds, followed by the application of the brake for 200 milliseconds.

C0204

The master cylinder pressure sensor signal indicates a change in master cylinder pressure which does not correlate with the signals from other sensors.

Action Taken When the DTC Sets
    • The EBCM disables the VSES.
    • The message center displays the SERVICE STABILITY SYSTEM message.

Conditions for Clearing the DTC

The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.

Diagnostic Aids

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to the following:

    •  Testing for Electrical Intermittents
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs
    •  Connector Repairs

Test Description

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

  1. This step tests the sensor circuitry in the low voltage range.

    2.

  2. This step tests the sensor circuitry in the high voltage range.

    3.

  3. This step tests the pressure transducer low reference circuit.

Step

Action

Values

Yes

No

Schematic Reference: Antilock Brake System Schematics

1

Did you perform the ABS Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

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 3

3
  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 4

Go to Diagnostic Aids

4

  1. Turn OFF the ignition.
  2. Disconnect the master cylinder pressure sensor harness connector. Refer to Brake Fluid Pressure Sensor Replacement .
  3. Turn ON the ignition.
  4. Install a scan tool.
  5. Select the VSES Data List on the scan tool.
  6. Observe the Master Cylinder Pressure Sensor Input voltage on the scan tool.

Is the Master Cylinder Pressure Sensor Input voltage less than the specified value?

0.15 V

Go to Step 5

Go to Step 9

5

  1. Turn OFF the ignition.
  2. Connect a 3 amp fused jumper wire between the pressure transducer supply voltage circuit and the pressure transducer sensor signal circuit. Refer to Using Fused Jumper Wires in Wiring Systems.
  3. Turn ON the ignition.
  4. Observe the Master Cylinder Pressure Sensor Input voltage on the scan tool.

Is the Master Cylinder Pressure Sensor Input voltage greater than the specified value?

4.75 V

Go to Step 6

Go to Step 7

6
  1. Disconnect the fused jumper wire.
  2. Use a DMM in order to measure the voltage between the pressure transducer supply voltage circuit and the pressure transducer low reference circuit.

Does the voltage measure greater than the specified value?

4.75 V

Go to Step 11

Go to Step 10

7

Test the pressure transducer supply voltage circuit for the following conditions.

    • An open
    • A high resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 8

8

Test the pressure transducer sensor signal circuit for the following conditions.

    • An open
    • A short to ground
    • A high resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 12

9

Test the pressure transducer sensor signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 14

10

Test the pressure transducer low reference circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 12

11

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

Did you find and correct the condition?

--

Go to Step 15

Go to Step 13

12

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

Did you find and correct the condition?

--

Go to Step 15

Go to Step 14

13

Replace the master cylinder pressure sensor. Refer to Brake Fluid Pressure Sensor Replacement .

Did you complete the replacement?

--

Go to Step 15

--

14

Important: Following EBCM replacement, use the scan tool to perform the Tire Size Calibration procedure.

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the replacement?

--

Go to Step 15

--

15
  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 3

System OK