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Home › Chrysler › 2006 › 300 Base, 42RLE/VLP › Repair and Diagnosis › Engine Performance › System › Engine Controls - DTCS P0481 To P0580 › Diagnosis And Testing › P0571-Brake Switch 1 Performance › Diagnostic Test

Diagnostic Test

  1. 1)  ACTIVE DTC 
    NOTE: Make sure the Stop Lamp Switch is properly adjusted before continuing.
    NOTE: Make sure the Stop Lamp Switch is properly wired, such as (B15) Brake Switch No.1 and (B16) Brake Lamp Switch No.2 circuits are not switched at the harness connector.

    Ignition on, engine not running.

    With a scan tool, read DTCs.

    Is the DTC active at this time? 

    Yes 

    1. Go To  2).

    No 

    1. Refer to INTERMITTENT CONDITION .
    2. Perform POWERTRAIN VERIFICATION TEST .
  2. 2)  (B15) BRAKE SWITCH NO.1 SIGNAL SHORTED TO GROUND 
    Fig 1: Checking Stop Lamp Switch Signal Circuit For Short To Ground
    GC0015055Courtesy of DAIMLERCHRYSLER CORP.

    Turn the ignition off.

    Disconnect the Stop Lamp Switch harness connector.

    Disconnect the PCM harness connectors.

    Measure the resistance between the (B15) Brake Switch No.1 Signal circuit in the Stop Lamp Switch harness connector and ground.

    Is the resistance below 100 ohms? 

    Yes 

    1. Repair the short to ground in the (B15) Brake Switch No.1 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go To  3).
  3. 3)  (B15) BRAKE SWITCH NO.1 SIGNAL OPEN 
    Fig 2: Checking Stop Lamp Switch 1 Signal Circuit
    GC0015054Courtesy of DAIMLERCHRYSLER CORP.
    CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

    Measure the resistance of the (B15) Brake Switch No.1 Signal circuit between the Stop Lamp Switch harness connector and the appropriate terminal of the special tool #8815.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go To  4).

    No 

    1. Repair the open in the (B15) Brake Switch No.1 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  4. 4)  (B16) BRAKE SWITCH NO.2 SIGNAL SHORTED TO GROUND 
    Fig 3: Checking Stop Lamp Switch 2 Signal Circuit
    GC0015058Courtesy of DAIMLERCHRYSLER CORP.

    Turn the ignition off.

    Disconnect the Stop Lamp Switch harness connector.

    Disconnect the PCM harness connectors.

    Measure the resistance between the (B16) Brake Switch No.2 Signal circuit in the Stop Lamp Switch harness connector and ground.

    Is the resistance below 100 ohms? 

    Yes 

    1. Repair the short to ground in the (B16) Brake Switch No.2 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go To  5).
  5. 5)  (B16) BRAKE SWITCH NO.2 SIGNAL OPEN 
    Fig 4: Checking Stop Lamp Switch 2 Signal Circuit
    GC0015057Courtesy of DAIMLERCHRYSLER CORP.
    CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

    Measure the resistance of the (B16) Brake Switch No.2 Signal circuit between the Stop Lamp Switch harness connector and the appropriate terminal of the special tool #8815.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go To  6).

    No 

    1. Repair the open in the (B16) Brake Switch No.2 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  6. 6)  (F202) FUSED IGNITION SWITCH OUTPUT (RUN-START) OPEN 
    Fig 5: Checking Stop Lamp Switch Supply Circuit
    GC0015059Courtesy of DAIMLERCHRYSLER CORP.

    Reconnect the PCM harness connector.

    Turn the ignition on.

    Using a 12-volt test light connected to ground, probe the (F202) Fused Ignition Switch Output circuit in the Stop Lamp Switch harness connector.

    Does the test light illuminate brightly? 

    Yes 

    1. Go To  7).

    No 

    1. Repair the open in the (F202) Fused Ignition Switch Output circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  7. 7)  (Z912) GROUND CIRCUIT OPEN 
    Fig 6: Checking Stop Lamp Switch Ground Circuit
    GC0015056Courtesy of DAIMLERCHRYSLER CORP.

    Using the 12-Volt test light connected to battery voltage, probe the (Z912) Ground circuit in the Stop Lamp Switch harness connector.

    Does the test light illuminate brightly? 

    Yes 

    1. Go To  8).

    No 

    1. Repair the open in the (Z912) Ground circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  8. 8)  STOP LAMP SWITCH 

    Remove the Stop Lamp Switch.

    Measure the resistance between terminals 1 and 2 of the Stop Lamp Switch.

    Next, measure the resistance between terminals 3 and 4 of the Stop Lamp Switch.

    Press and release the Stop Lamp Switch while monitoring the ohmmeter during both of the above steps.

    Does the resistance change from below 5.0 ohms to an open circuit for one or both of the measurements taken? 

    Yes 

    1. Go To  9).

    No 

    1. Replace the Stop Lamp Switch.
    2. Perform POWERTRAIN VERIFICATION TEST .
  9. 9)  PCM 
    NOTE: Before continuing, check the PCM harness connector 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.

    Were there any problems found? 

    Yes 

    1. Repair as necessary.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Replace and program the Powertrain Control Module per Service Information.
    2. Perform POWERTRAIN VERIFICATION TEST .
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