GM Service Manual Online
For 1990-2009 cars only

DTC C0201 Under 8600 GVW

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC C0201 00: Antilock Brake System (ABS) Enable Relay Contact Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Antilock Brake System (ABS) Enable Relay Contact Circuit

C0201 00

C0201 00

C0201 00

Circuit/System Description

The solenoid relay, located within the electronic brake control module (EBCM), supplies battery voltage to all of the valve solenoids.

Conditions for Running the DTC

    • Ignition voltage is greater than 9.5 volts.
    • The solenoid relay is commanded ON.

Conditions for Setting the DTC

One or more of the following conditions exists:

    • The EBCM detects an open in the battery positive voltage circuit to the solenoid valve relay.
    • The EBCM detects a stuck open solenoid valve relay or an open circuit between the solenoid valve relay and solenoid valves.

Action Taken When the DTC Sets

    • The EBCM disables the Antilock Brake System (ABS)/Traction Control System (TCS)/dynamic rear proportion (DRP) for the duration of the ignition cycle.
    • The ABS indicator turns ON.
    • The Traction Control indicator turns ON.
    • The red brake warning indicator turns ON.
    • The driver information center (DIC) displays the SERVICE BRAKE SYSTEM/TRACTION SYSTEM message.

Conditions for Clearing the DTC

    • The condition for setting the DTC is no longer present.
    • The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Antilock Brake System Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Scan Tool Data List for EBCM

Circuit/System Verification

With scan tool installed, clear the DTCs then drive the vehicle in a straight line at a speed greater than 20 km/h (13 mph). If the DTC did not set as a current DTC see diagnostic aids.

Circuit/System Testing

  1. Test for an open or a short to ground in the battery positive voltage circuit to the EBCM. Verify no open or a short to ground is found.
  2. Test the EBCM ground circuit, an open or high resistance.
  3. If an open or a short to ground is found, repair the circuit.
  4. Replace the EBCM assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for EBCM replacement, setup, and programming

DTC C0201 Equal to or over 8600 GVW

Circuit Description

The system relay, located within the electronic brake control module (EBCM), supplies battery voltage to all of the valve solenoids and to the Antilock Brake System (ABS) pump motor. When the relay contacts close, the EBCM monitors the voltage supplied to the valve solenoids and compares this voltage to monitored ignition voltage.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0201 Antilock Brake System (ABS) Enable Relay Contact Circuit

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The EBCM detects that the voltage supplied to the valve solenoids is less than 80 percent of monitored ignition voltage for 50 milliseconds.

Action Taken When the DTC Sets

    • The EBCM disables the ABS/DRP.
    • The ABS indicator turns ON.
    • The brake warning indicator turns ON.

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

Refer back to the diagnostic table, steps 3-7, if this DTC continues to set intermittently.

Test Description

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

  1. A shorted ABS pump motor may damage the contacts within the system relay. It is imperative that the steps in the table be followed to prevent damage to a replacement EBCM.

Step

Action

Values

Yes

No

Schematic Reference: Antilock Brake System Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Use a scan tool in order to clear the DTCs.
  2. Use the scan tool in order to perform an Antilock Brake System (ABS) Function Test.

Does the DTC set?

--

Go to Step 3

Go to Diagnostic Aids

3

  1. Separate the electronic brake control module (EBCM) from the brake pressure l modulator valve (BPMV). Refer to Electronic Brake Control Module Replacement .
  2. Use a DMM in order to measure the resistance across the ABS pump motor.

Does the resistance measure within the specified range?

0.3-1.0 ohms

Go to Step 4

Go to Step 6

4

Use a DMM in order to measure the resistance between the high side of the pump motor and a good ground.

Does the resistance measure less than the specified value?

0L

Go to Step 6

Go to Step 5

5

Replace the EBCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 7

--

6

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

  1. Replace the EBCM, refer to Control Module References for replacement, setup, and programming.
  2. Replace the BPMV, refer to Brake Pressure Modulator Valve Replacement .

Did you complete the replacements?

--

Go to Step 7

--

7

  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