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Diagnostic Test

WARNING: This page is about a different car, the 2006 Chrysler PT Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
  1. 1)  GOOD TRIP INDICATED 

    Turn the ignition on.

    NOTE: This DTC can be set if the vehicle operator "rides" the brake pedal. Check with vehicle operator to ensure that they are not resting one of their feet on the brake pedal while driving.
    NOTE: This DTC can be set if the brake pedal switch is not adjusted properly. Check brake pedal switch for proper adjustment before continuing.

    With the scan tool, read DTC's.

    Does the Good Trip Indicator display NO? 

    Yes 

    1. Go To  2).

    No 

    1. Refer to the INTERMITTENT CONDITION diagnostic procedure.
    2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
  2. 2)  (A924) FUSED B+ CIRCUIT 
    Fig 1: CHECKING FUSED B+ CIRCUIT
    GC0041964Courtesy of DAIMLERCHRYSLER CORP.

    Turn the ignition off.

    Disconnect the Brake Lamp Switch harness connector.

    Using a 12-volt test light connected to ground, probe the (A924) Fused B+ circuit in the Brake Lamp Switch harness connector.

    Does the test light illuminate brightly? 

    Yes 

    1. Go To  3).

    No 

    1. Repair the (A924) Fused B+ circuit.
    2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
  3. 3)  (B15) BRAKE SWITCH SIGNAL CIRCUIT OPEN 
    Fig 2: MEASURING RESISTANCE OF BRAKE SWITCH SIGNAL CIRCUIT
    GC0041965Courtesy of DAIMLERCHRYSLER CORP.

    Disconnect the PCM harness connector.

    Measure the resistance of the (B15) Brake Switch Signal circuit between the Brake Lamp Switch harness connector and the PCM harness connector.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go To  4).

    No 

    1. Repair the open in the (B15) Brake Switch Signal circuit.
    2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
  4. 4)  (B15) BRAKE SWITCH SIGNAL SHORTED TO GROUND 
    Fig 3: MEASURING RESISTANCE OF BRAKE SWITCH SIGNAL CIRCUIT
    GC0041966Courtesy of DAIMLERCHRYSLER CORP.

    Measure the resistance of the (B15) Brake Switch Signal circuit in the Brake Lamp Switch harness connector to ground.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Repair the short to ground in the (B15) Brake Switch Signal circuit.
    2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .

    No 

    1. Go To  5).
  5. 5)  (B15) BRAKE SWITCH SIGNAL CIRCUIT SHORTED TO VOLTAGE 
    Fig 4: MEASURING VOLTAGE OF BRAKE SWITCH SIGNAL CIRCUIT
    GC0041967Courtesy of DAIMLERCHRYSLER CORP.

    Turn the ignition on.

    Measure the voltage of the (B15) Brake Switch Signal circuit in the Brake Lamp Switch harness connector.

    Is the voltage above 1.0 volts? 

    Yes 

    1. Repair the short to voltage in the (B15) Brake Switch Signal circuit.
    2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .

    No 

    1. Go To  6).
  6. 6)  (Z902) GROUND CIRCUIT OPEN 
    Fig 5: MEASURING RESISTANCE OF GROUND CIRCUIT
    GC0041968Courtesy of DAIMLERCHRYSLER CORP.

    Measure the resistance of the (Z902) Ground circuit in the Brake Lamp Switch harness connector to ground.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go To  7).

    No 

    1. Repair the open in the (Z902) Ground circuit.
    2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
  7. 7)  BRAKE LAMP SWITCH OPERATION 
    Fig 6: CHECKING BRAKE LAMP SWITCH OPERATION
    GC0041969Courtesy of DAIMLERCHRYSLER CORP.

    Measure the resistance between the (Z902) Ground circuit terminal and the (B15) Brake Switch Signal terminal in the Brake Lamp Switch.

    Apply and release the brake pedal while monitoring the ohmmeter.

    Does the resistance change from below 5.0 ohms to open circuit? 

    Yes 

    1. Go To  8).

    No 

    1. Replace the Brake Lamp Switch.
    2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
  8. 8)  PCM 
    NOTE: Before Continuing: Disconnect the PCM harness connector and check the related wiring terminals for corrosion, damage or terminal push out. Repair as necessary.

    Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

    If there are no possible causes remaining, view repair. 

    Repair 

    1. Replace and program the Powertrain Control Module in accordance with the Service Information. (Refer to STANDARD PROCEDURE - PCM/ECM/SKREEM PROGRAMMING) .
    2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
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