GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2002 🢒 GMC C Cab/Chassis HD (GMT 400) 🢒 DTC 🢒 DTC C0288 or C088

Circuit Description

The EBCM illuminates the brake warning indicator by supplying ground to the lamp. When the brake warning indicator is commanded ON, the feedback voltage to the EBCM from the ABS pressure differential sensor signal circuit is low.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The EBCM detects high feedback voltage from the ABS pressure differential sensor signal circuit when the brake warning indicator is commanded ON.

Action Taken When the DTC Sets

This information-only DTC is stored in EBCM memory until it is cleared by using the specified procedure.

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

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to the following:

    •  Testing for Electrical Intermittents
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs
    •  Connector Repairs

Test Description

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

  1. The EBCM may be damaged if the ABS pressure differential sensor signal circuit is shorted to voltage.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

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. Turn OFF the ignition for 5 seconds.
  3. Turn ON the ignition and observe the scan tool.

Does the DTC set?

Go to Step 3

Go to Diagnostic Aids

3
  1. Turn OFF the ignition.
    2. • For vehicles with DRLs, disconnect the daytime running lamps control module harness connector. Refer to Daytime Running Lights (DRL) Control Module Replacement in Lighting Systems.
    •  For vehicles without DRLs, remove the instrument panel cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.
  2. Turn ON the ignition.
  3. Use a scan tool in order to clear the DTC.
  4. Turn OFF the ignition for 5 seconds.
  5. Turn ON the ignition and observe the scan tool.

Does the DTC set?

Go to Step 4

Go to Step 5

4

Test the ABS pressure differential sensor signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 7

5

Inspect for poor connections at the harness connector of the daytime running lamps control module or instrument panel cluster. 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 9

Go to Step 6

6

Replace the daytime running lamps control module or the instrument panel cluster. Refer to Daytime Running Lights (DRL) Control Module Replacement in Lighting Systems or Instrument Cluster Replacement in Instrument Panel, Gages, and Console.

Did you complete the replacement?

Go to Step 9

--

7

Inspect for poor connections at the harness connector of the EBCM. 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 9

Go to Step 8

8

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

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the replacement?

Go to Step 9

--

9
  1. Use the scan tool in order to clear the DTC.
  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