GM Service Manual Online
For 1990-2009 cars only

Object Number: 585709  Size: LF
ABS Components
Antilock Brake System Schematics
Power Distribution Schematics
Power Distribution Schematics
Handling Electrostatic Discharge Sensitive Parts Notice

Circuit Description

The EBCM monitors the voltage at the Ignition Positive Voltage input and the Battery Positive Voltage circuit at the switch side of the Electronic Brake Control Relay. The voltage at the switch side of the Electronic Brake Control Relay is referred to as the system voltage. The EBCM uses both of the voltages in order to determine if a low voltage condition exists. A low voltage condition prevents the ABS/TCS system from operating properly.

Conditions for Running the DTC

    • The vehicle speed is greater than 8 km/h (5 mph).
    • The ignition voltage is no more than 10.8 volts.
    • The electronic brake control relay is commanded ON.

AND

Criteria 1

The ABS pump motor is OFF.

OR

Criteria 2

ABS is in initialization.

OR

Criteria 3

ABS or TCS is active.

Conditions for Setting the DTC

Either of the following criteria is present for greater than 0.72 seconds.

Criteria 1 and Criteria 2

The system voltage is no more than 10.8 volts.

OR

Criteria 3

The system voltage is no more than 9.36 volts.

Action Taken When the DTC Sets

    •  ABS/TCS is disabled.
    • ABS/TCS Indicators are turned on.

Conditions for Clearing the DTC

    • Condition for DTC is no longer present.
    • The Scan Tool clear DTC function is used.
    • 100 Ignition cycles have passed with no DTCs detected.

Step

Action

Value(s)

Yes

No

1

Did you perform the ABS Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Install a scan tool.
  2. Start the engine.
  3. With a scan tool, observe the Ignition Voltage parameter in ABS/TCS data list.

Does the scan tool indicate the ignition voltage is greater than specified value?

10.8 V

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

With a scan tool, observe the Electronic Battery Feed parameter in the BCM data list.

Does the scan tool indicate the electronic battery feed is greater than specified value?

10.8 V

Go to Step 4

Go to Battery Inspection/Test

4

Test the module ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

 

Go to Step 7

Go to Step 5

5

Inspect for poor connections/terminal tension at the EBCM harness connector. 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 7

Go to Step 6

6

Replace the EBCM. Refer to Electronic Brake Control Module Replacement

Did you complete the replacement?

--

Go to Step 7

--

7

  1. Clear the DTCs using the scan tool.
  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