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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 421 (Engine Control System Self-Diagnostics - 3.8L) >> Diagnostic Tests >> DTC P0724: TCC Brake Switch Circuit - High Input >> Diagnostic Procedures

Diagnostic Procedures

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  1. Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
    2. NOTE: Before clearing the DTCs, use the scan tool in order to record the Failure Records for reference. Using the CLEAR INFO function will erase the stored Failure Records from the PCM.
  2. Install a scan tool. Turn ignition on, with engine off. Record the Failure Records. Clear the DTCs. With a scan tool, observe the TCC BRAKE SWITCH parameter. Apply the brake pedal. Does the scan tool display OPEN? If yes, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
    3. CAUTION: When you are performing service on or near the SIR components or the SIR wiring, you must disable the SIR system. See appropriate AIR BAG RESTRAINT SYSTEMS article in ACCESSORIES & EQUIPMENT. Failure to follow the correct procedure could cause air bag deployment, personal injury, or unnecessary SIR system repairs.
  3. Turn off the ignition. Disconnect the TCC brake switch 4-way connector. Turn ignition on, with engine off. With a scan tool, observe the TCC BRAKE SWITCH parameter. Does the scan tool display OPEN? If yes, go to step  5. If no, go to next step.
  4. Test the signal circuit (CKT 420) of the TCC brake switch for a short to power between the PCM and the TCC brake switch. Did you find and correct the condition? If yes, go to step  7. If no, go to step  6.
  5. Replace the TCC brake switch. After repairs, go to step  7.
  6. Replace PCM. Program replacement PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  7. Perform the following procedure in order to verify the repair:
    • Select DTC.
    • Select CLEAR INFO.
    • Turn ignition on, with engine off.
    • Apply brake pedal. The TCC brake switch must be open for more than 2 seconds.
    • Select SPECIFIC DTC.
    • Enter DTC P0724.

    Has the test run and passed? If yes, system is okay. If no, go to step  1.

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