GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Prizm 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C0900

Circuit Description

The EBCM monitors the ignition positive voltage level available for ABS operation. If the voltage level is too high, damage may result in the system.

Conditions for Running the DTC

The ignition switch is in the ON position.

Conditions for Setting the DTC

The ignition positive voltage is greater than 17 volts.

Action Taken When the DTC Sets
    • The ABS is disabled.
    • The ABS warning indicator turns ON.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

Diagnostic Aids

The following are possible causes of the DTC:

    • A charging system malfunction
    • An internal EBCM malfunction

Test Description

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

  1. This step uses the scan tool to check the ignition positive voltage circuit to the EBCM.

    2.

  2. This step checks the ignition positive voltage supply circuit.

Step

Action

Value(s)

Yes

No

Schematic Reference: Antilock Brake System Schematics

1

Did you perform A Diagnostic System Check - ABS?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Turn OFF all of the accessories.
  2. Install a scan tool.
  3. Start the engine.
  4. Run the engine at approximately 2000 RPM.
  5. With a scan tool, observe the Ignition Voltage parameter in the ABS data list.

Does the scan tool indicate that the ignition voltage is less than the specified voltage?

17 V

Go to Step 5

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the EBCM harness connector.
  3. Start the engine.
  4. Run the engine at approximately 2000 RPM.
  5. Measure the voltage between the ignition positive voltage circuit of the EBCM and a good ground.

Does the voltage measure less than the specified value?

17 V

Go to Step 4

Go to Symptoms - Engine Electrical in Engine Electrical

4
  1. Use the scan tool in order to clear the DTCs.
  2. Carefully test drive the vehicle at a speed above 8 km/h (5 mph).

Does the DTC reset?

--

Go to Step 5

System OK

5

Replace the Brake Pressure Modulator Valve (BPMV). Refer to Brake Pressure Modulator Valve Assembly Replacement .

Did you complete the replacement?

--

Go to Step 6

--

6
  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