SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 724 (ANTILOCK BRAKE SYSTEM, TRACTION CONTROL SYSTEM & STABILITY CONTROL SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC C1254TEST DESCRIPTION
1999 GMC Forward Control 5.7 R, Automatic

Test Description

1999 GMC Forward Control 5.7 R, AutomaticSECTION Test Description
WARNING: This page is about a different car, the 2004 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 2:  Tests for an open in the ground circuits of the EBCM.
  2. 4:  Verifies the proper operation of the charging system.
  3. 6:  Determines whether the DTC resets.
DTC C1254

Step Action Yes No
Schematic Reference:  ABS Schematics  
Connector End View Reference:  ABS Connector End Views  
1 Did you perform the ABS Diagnostic System Check? Go to Step 2  Go to Diagnostic System Check - ABS 
2 
  1. Turn OFF the ignition.
  2. Disconnect the EBCM harness connector.
  3. Install the J 39700 universal breakout box using the J 39700-300  cable adapter to the EBCM harness connector only. See Special Tools and Equipment .
  4. Test both ground circuits of the EBCM including the EBCM ground for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 8  Go to Step 3 
3 Has the battery been disconnected recently? Go to Step 8  Go to Step 4 
4  Test the charging system. Refer to Diagnostic System Check - Engine Electrical in Engine Electrical.
Did you find and correct the condition?		 Go to Step 8  Go to Step 5 
5 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 8  Go to Step 6 
6 
  1. Use the scan tool in order to clear the DTCs.
  2. With the scan tool, perform the Automated Test.
Does the DTC reset?		 Go to Step 7  Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
7 Replace the EBCM. Refer to Electronic Brake Control Module Replacement .
Did you complete the repair?		 Go to Step 8  -
8
  1. Use the scan tool in order to clear the DTCs.
  2. With the scan tool, perform the Automated Test.
Does the DTC reset?		 Go to Step 2  System OK
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.