SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1780 (ANTILOCK BRAKE SYSTEM AND TCS)DIAGNOSTIC INFORMATION AND PROCEDURESTRACTION CONTROL INDICATOR ALWAYS ONDIAGNOSTIC AIDS
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Diagnostic Aids

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Diagnostic Aids
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  • 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.
  • Thoroughly inspect any circuitry that may be causing the complaint for the following conditions:
    • Backed out terminals
    • Improper mating
    • Broken locks
    • Improperly formed or damaged terminals
    • Poor terminal-to-wiring connections
    • Physical damage to the wiring harness
  • The following conditions may cause an intermittent malfunction:
    • A poor connection
    • Rubbed-through wire insulation
    • A broken wire inside the insulation
  • If an intermittent malfunction exists refer Inducing Intermittent Fault Conditions for further diagnosis.
Traction Control Indicator Always On

Step Action Yes No
Schematic Reference: Antilock Brake System Schematics 
Connector End View Reference: Antilock Brake System Connector End Views  or CELL LINK 
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle
2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Traction Switch parameter in the body control module (BCM) data display, inputs.
  4. Activate the traction control switch.
Does the Traction Switch parameter change state?		 Go to Testing for Intermittent Conditions and Poor Connections Go to Step 3 
3
  1. Turn OFF the ignition.
  2. Disconnect the traction control switch connector.
  3. Connect a fused jumper from the signal circuit of the traction control switch harness connector to a good ground.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, observe the Traction Switch parameter.
Does the scan tool display Active ?		 Go to Step 5  Go to Step 4 
4 Test the signal circuit of the traction control switch for an open or high resistance. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 Go to Step 10  Go to Step 6 
5 Test the ground circuit of the traction control switch for an open or high resistance. Refer to and Testing for Continuity .
Did you find and correct the condition?		 Go to Step 10  Go to Step 7 
6 Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 Go to Step 10  Go to Step 8 
7 Inspect for poor connections at the harness connector of the traction control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 Go to Step 10  Go to Step 9 
8 Replace the BCM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 Go to Step 10  -
9 Replace the traction control switch. Refer to Electronic Traction Control Switch Replacement .
Did you complete the replacement?		 Go to Step 10  -
10 Operate the system in order to verify the repair.
Did you correct the condition?		 System OK Go to Step 2 
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.