GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The EBCM internal relay supplies battery voltage to all eight valve solenoids and to the pump motor. The EBCM microprocessor applies the grounds needed to activate each solenoid. The low side of each solenoid coil has a feedback circuit to the EBCM microprocessor. When a solenoid is commanded off, the feedback voltage is high. When a solenoid is commanded on, the feedback voltage is low.

Conditions for Running the DTC

    • The ignition is ON.
    • The vehicle is experiencing an ABS event.

Conditions for Setting the DTC

The EBCM commands a dump or isolation solenoid ON for greater than 28 seconds.

Action Taken When the DTC Sets

If equipped, the following actions occur.

    • The EBCM disables ABS/TCS.
    • The ABS indicator turns ON.
    • The traction off 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

The most likely cause of this DTC is a mechanical failure that causes a wheel to lock and remain locked. The DTC may also set, conceivably, when the ABS is activated on surfaces that are nearly impossible to get traction on. If the DTC sets within these conditions, diagnosis of the ABS system is not necessary.

Test Description

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

  1. Performing Solenoid Tests determines if there is a mechanical malfunction inside the BPMV.

Step

Action

Yes

No

1

Did you perform the ABS Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Use a scan tool in order to clear the DTCs.
  2. Use the scan tool in order to perform the necessary Solenoid Tests. Refer to Scan Tool Output Controls .

Do the Solenoid Tests show the system to be functioning normally?

Go to Diagnostic Aids

Go to Step 3

3

Replace the BPMV. Refer to Brake Pressure Modulator Valve Replacement .

Did you complete the replacement?

Go to Step 4

--

4

Use the scan tool in order to perform the necessary Solenoid Tests.

Do the Solenoid Tests show the system to be functioning normally?

System OK

Go to Step 3