GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Prizm 🢒 Brakes 🢒 Antilock Brake System 🢒 Scan Tool Displays Undefined DTC

Circuit Description

The Electronic Brake Control Module (EBCM) interfaces with a scan tool through terminal 4 via the OBD2 Data Link Connector (DLC) terminal 7. A properly set scan tool connected to the DLC can retrieve ABS diagnostic information like Diagnostic Trouble Codes (DTCs) and perform ABS device control for testing purposes.

Diagnostic Aids

Inspect the following list of items when diagnosing this part of the Antilock Brake System (ABS):

    • Scan tool in good working order
    • Scan tool with correct software

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Performs undefined DTC confirmation.

    2.

  2. Performs undefined DTC confirmation with a known good scan tool.

Step

Action

Value(s)

Yes

No

1

Did you perform A Diagnostic System Check - ABS?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Turn the ignition switch to the LOCK position.
  2. Connect a scan tool to the OBD2 Data Link Connector (DLC).
  3. Turn the ignition switch to the ON position.
  4. Select Diagnostic Trouble Codes (DTCs) from Application Menu on the scan tool.
  5. Select DTC Information on the scan tool.
  6. Record the undefined DTCs.
  7. Turn the ignition switch to the LOCK position.
  8. Disconnect the scan tool from the DLC.
  9. Test drive the vehicle at 24 km/h (15 mph) for 30 seconds.
  10. When driving conditions permit, perform an ABS stop and bring the vehicle to a complete stop.
  11. Connect a scan tool to the Data Link Connector (DLC).
  12. Select Diagnostic Trouble Codes (DTCs) from Application Menu on the scan tool.
  13. Select DTC Information on the scan tool.
  14. Select Current DTC on the scan tool.

Does the undefined DTC reset?

--

Go to Step 3

Go to Step 5

3

  1. Disconnect the scan tool from the DLC.
  2. Connect a known-good scan tool to the OBD2 Data Link Connector (DLC).
  3. Turn the ignition switch to the ON position.
  4. Select the Diagnostic Trouble Codes (DTCs) from Application Menu on scan tool.
  5. Select DTC Information on the scan tool.
  6. Read DTCs on the scan tool.

Does the undefined DTC reset?

--

Go to Step 4

Go to Step 5

4

Replace the brake pressure modulator valve assembly. Refer to Brake Pressure Modulator Valve Assembly Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

5

A malfunction is not present at this time. Refer to Diagnostic Aids for additional information regarding this condition.

Is the action complete?

--

Go to Diagnostic System Check - ABS

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