GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2004 🢒 Epica 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C0094

Circuit Description

This DTC is used to identify the conditions of the brake switch circuit. The electronic brake control module (EBCM) sends a low current 5-volt sense voltage on brake switch input line to the rear brake light bulbs. If the rear brake light circuit is intact, this voltage will be pulled low, under 1 volt, to ground through the rear brake light bulbs. When the brake light switch is depressed, battery voltage will be supplied to the rear brake lights and to the EBCM, indicating the brake lights are ON.

Conditions for Setting the DTC
    • Out of adjustment or shorted brake switch contacts
    • Brake switch circuit shorted to battery
    • Internal EBCM fault

Action Taken When the DTC Sets

The antilock brake system (ABS) remains functional.

Conditions for Clearing the DTC
    • If the conditions that set the DTC C0094 are no longer present, the DTC can be cleared by scan tool.
    • The DTC that has not occurred in 100 drive cycles will be cleared from the history data.

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check-ABS?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

Check the brake lamp function without applying brake pedal.

Does the brake lamp turn ON?

--

Go to Step 3

Go to Step 4

3

Disconnect the brake switch connector.

Does the brake lamp turn ON again?

--

Go to Step 5

Go to Step 8

4
  1. Disconnect the electronic brake control module (EBCM) connector.
  2. Check the voltage between the terminal 7 of the EBCM wiring harness connector and the ground.

Is the voltage equal to the specified value?

0 V

Go to Step 5

Go to Step 6

5
  1. Repair the power short of the brake switch.
  2. Connect the scan tool and remove the DTC.
  3. Inspect the ABS function.

Did you find and correct the condition?

--

System OK

--

6
  1. Connect the EBCM connector.
  2. Connect the scan tool and remove the DTC.
  3. Operate the ABS with the scan tool.
  4. Replace the EBCM only if you found DTC C0094.

Did you complete the replacement?

--

System OK

--

7

Inspect the brake lamp switch adjustment. Refer to Stop Lamp Switch Adjustment in Lighting Systems.

Did the brake lamp switch adjustment correct the condition?

--

System OK

Go to Step 8

8
  1. Replace the brake switch.
  2. Connect the scan tool and remove the DTC.
  3. Inspect the ABS function.

Did you complete the replacement?

--

System OK

--