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Home >> Jeep >> 2008 >> Commander Base, 4.7 N, AWD >> Repair and Diagnosis >> Engine Performance >> System >> DTCS P0703 To P2072 >> P0703-Brake Switch 2 Performance >> Diagnostic Test

Diagnostic Test

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

    Ignition on, engine not running.

    With a scan tool, select View DTCs.

    Is the DTC Active at this time? 

    Yes 

    1. Go To  2.

    No 

    1. Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
  2. (F942) FUSED IGNITION SWITCH CIRCUIT 
    Fig 1: Checking Speed Control Brake Switch Output Circuit
    GC0027163Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the Stop Lamp Switch harness connector.

    Using a 12-volt test light connected to ground, probe the (F942) Fused Ignition Switch Output circuit in the Stop Lamp Switch harness connector.

    Does the test light illuminate brightly? 

    Yes 

    1. Go To  3.

    No 

    1. Repair the open or short to ground in the (F942) Fused Ignition Switch Output circuit. Inspect the related fuse and repair as necessary.
    2. Perform POWERTRAIN VERIFICATION TEST .
  3. STOP LAMP SWITCH 

    Turn the ignition off.

    Measure the resistance between the (F942) Fused Ignition Switch Output circuit terminal and the (B16) Brake Switch No.2 Signal circuit terminal in the Stop Lamp Switch.

    Measure the resistance between the (Z904) Ground circuit terminal and the (B15) Brake Switch No.1 Signal terminal in the Stop Lamp Switch.

    Apply and release the Stop Lamp Switch while monitoring the ohmmeter.

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

    Yes 

    1. Go To  4.

    No 

    1. Verify that there is good pin to terminal contact in the Switch and Powertrain Control Module connectors. If OK, replace the Stop Lamp Switch.
    2. Perform POWERTRAIN VERIFICATION TEST .
  4. (B16) BRAKE SWITCH NO.2 SIGNAL CIRCUIT SHORTED TO VOLTAGE 
    Fig 2: Checking Brake Switch No. 2 Signal Circuit
    GC0027185Courtesy of CHRYSLER LLC

    Disconnect the C3 PCM harness connector.

    Measure the voltage on the (B16) Brake Switch No.2 Signal circuit in the Stop Lamp Switch harness connector.

    Ignition on, engine not running.

    Is there any voltage present? 

    Yes 

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

    No 

    1. Go To  5.
  5. (B16) BRAKE SWITCH NO.2 SIGNAL CIRCUIT OPEN 
    Fig 3: Checking Brake Switch No. 2 Signal Circuit For Open
    GC0027145Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Measure the resistance of the (B16) Brake Switch No.2 Signal circuit from the Stop Lamp Switch harness connector to the appropriate terminal of 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. (B16) BRAKE SWITCH NO.2 SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 4: Checking Speed Control Supply/Brake Switch No. 2 Signal Circuit Short To Ground
    GC0027146Courtesy of CHRYSLER LLC

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

    Is the resistance below 5.0 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  7.
  7. (B15) BRAKE SWITCH NO.1 SIGNAL CIRCUIT OPEN 
    Fig 5: Checking Brake Switch No. 1 Signal Circuit Open
    GC0027149Courtesy of CHRYSLER LLC

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

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go To  8.

    No 

    1. Repair the open in the (B15) Brake Switch No.1 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  8. POWERTRAIN CONTROL MODULE (PCM) 

    Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Stop Lamp Switch and the Powertrain Control Module (PCM).

    Look for any chafed, pierced, pinched, or partially broken wires.

    Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Switch and Powertrain Control Module connectors.

    Refer to any Technical Service Bulletins that may apply.

    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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