LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Jeep >> 2007 >> Compass Limited, AWD, Standard >> Repair and Diagnosis >> Engine Performance >> System >> DTCS P0271 To P0441 >> P0325-Knock Sensor 1 Circuit >> Diagnostic Test
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Test

  1. 1) DTC IS ACTIVE 

    Start the engine and allow it to reach normal operating temperature.

    WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.
    NOTE: It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to reset.

    Raise the engine speed to 2700 RPM for a minimum of 30 seconds.

    With the scan tool, select View DTCs.

    Is the status Active for this DTC? 

    Yes 

    1. Go to  2).

    No 

    1. Refer to the *CHECKING FOR AN INTERMITTENT CONDITION Diagnostic Procedure.
  2. 2) (K42) KS SIGNAL CIRCUIT SHORTED TO VOLTAGE 
    Fig 1: Measuring Voltage Of (K42) KS Signal Circuit In Knock Sensor Harness Connector
    GC0054085Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the Knock Sensor connector.

    Disconnect the Powertrain Control Module (PCM) connector.

    Turn the ignition on.

    Measure the voltage of the (K42) KS Signal circuit in the Knock Sensor harness connector.

    Is there any voltage present? 

    Yes 

    1. Repair the (K42) KS Signal circuit for a short to voltage.
    2. Perform PCM VERIFICATION TEST .

    No 

    1. Go to  3).
  3. 3) (K42) KS SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 2: Checking KS Signal Circuit For Short To Ground
    GC0054086Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Measure the resistance between ground and the (K42) KS Signal circuit in the Knock Sensor harness connector.

    Is the resistance above 100 ohms? 

    Yes 

    1. Go to  4).

    No 

    1. Repair the (K42) KS Signal circuit for a short to ground.
    2. Perform PCM VERIFICATION TEST .
  4. 4) (K42) KS SIGNAL CIRCUIT SHORTED TO (K942) KS RETURN CIRCUIT 
    Fig 3: Checking KS Signal Circuit For Short To Return Circuit
    GC0054087Courtesy of CHRYSLER LLC

    Measure the resistance between the (K42) KS Signal circuit and the (K942) KS Return circuit in the Knock Sensor harness connector.

    Is the resistance above 100 ohms? 

    Yes 

    1. Go to  5).

    No 

    1. Repair the (K42) KS Signal circuit for a short to the (K942) KS Return circuit.
    2. Perform PCM VERIFICATION TEST .
  5. 5) (K42) KS SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE 
    Fig 4: Checking KS Signal Circuit For Open Or High Resistance
    GC0054088Courtesy of CHRYSLER LLC

    Measure the resistance of the (K42) KS Signal circuit between the Knock Sensor harness connector and the Powertrain Control Module (PCM) harness connector.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go to  6).

    No 

    1. Repair the (K42) KS Signal circuit for an open circuit or high resistance.
    2. Perform PCM VERIFICATION TEST .
  6. 6) (K942) KS RETURN CIRCUIT OPEN OR HIGH RESISTANCE 
    Fig 5: Checking KS Return Circuit For Open Or High Resistance
    GC0054089Courtesy of CHRYSLER LLC

    Measure the resistance of the (K942) KS Return circuit between the Knock Sensor harness connector and the Powertrain Control Module (PCM) harness connector.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go to  7).

    No 

    1. Repair the (K942) KS Return for an open circuit or high resistance.
    2. Perform PCM VERIFICATION TEST .
  7. 7) KNOCK SENSOR 

    Turn the ignition off.

    Connect the Powertrain Control Module (PCM) connector.

    Replace the Knock Sensor in accordance with the Service Information.

    Start the engine and allow it to reach normal operating temperature.

    With the scan tool, select View DTCs.

    Is status Active for this DTC? 

    Yes 

    1. Go to  8).

    No 

    1. Test Complete.
    2. Perform PCM VERIFICATION TEST .
  8. 8) POWERTRAIN CONTROL MODULE (PCM) 

    Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Knock Sensor 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.

    Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.

    Look for the data to change or for the DTC to reset during the wiggle test.

    Refer to any Technical Service Bulletins that may apply.

    Were any problems found? 

    Yes 

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

    No 

    1. Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information.
    2. Perform PCM VERIFICATION TEST .
scientia non olet · About LEMON Manuals