GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Corvette 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C1294 Brake Lamp Switch Circuit Always Active

Object Number: 568150 Size: MF
ABS Components
Antilock Brake System Schematics

Circuit Description

This DTC occurs when internal self checking safety logic has determined that the Stoplamp Switch is continuously on. This is important because the TCS/Active Handling (if equipped with RPO JL4) can not be activated when the Stoplamp Switch is on.

Conditions for Setting the DTC

DTC C1294 can be set if the vehicle speed reaches at least 40 km/h (25 mph). If the brake was never off during two consecutive drive cycles, a malfunction exists.

Action Taken When the DTC Sets

ABS remains enabled, TCS/ Active Handling™ (if equipped with RPO JL4) are disabled.

    • Indicators that turn on:
        Car Icon (TCS indicator
    • Messages displayed on the DIC:
        Service Traction System
        Service Active HNDLG (if equipped with RPO JL4)

Conditions for Clearing the DTC
    • Condition for DTC is no longer present and scan tool clear DTC function is used.
    • Fifty ignition cycles have passed with no DTCs detected.

Diagnostic Aids
    • It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
    • Possible causes:
       - Stoplamp switch circuit shorted to voltage.
       - Stoplamp switch misadjusted or shorted.
       - Binding pedal.

DTC C1294 Brake Lamp Switch Circuit Always Active

Step

Action

Value(s)

Yes

No

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

Observe rear brake lamps.

Are brake lamps off?

--

Go to Step 4

Go to Step 3

3

Disconnect the Stoplamp switch connector.

Are the brake lamps ON?

--

Go to Step 6

Go to Step 7

4
  1. Disconnect the EBCM harness connector.
  2. Install J 39700 Universal Pinout Box using the J 39700-25 adapter cable to the EBCM harness connector only.
  3. Using J 39200 DMM, measure the voltage between the J 39700 terminals 9 and B.

Is the voltage within the range specified in the value(s) column?

Greater than 1 V

Go to Step 6

Go to Step 5

5
  1. Turn the ignition switch to the OFF position.
  2. Inspect CKT 20 and the EBCM harness connector for damage which may result in a short to voltage with all connector connected.
  3. Reconnect all connectors.
  4. Carefully drive vehicle for three drive cycles while monitoring a scan tool. A drive cycle consists of starting the engine, driving above 40 km/h (25 mph) back to 0 km/h (0 mph) and then turning the ignition OFF.

Was DTC C1294 set in the last three drive cycles?

--

Go to Step 8

Go to Diagnostic System Check - ABS

6

Repair short to voltage in CKT 20. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

7

Adjust or replace the Stoplamp switch as necessary. Refer to Stop Lamp Switch Adjustment in Hydraulic Brakes.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

8

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

Is the replacement complete?

--

Go to Diagnostic System Check - ABS

--