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Diagnostic Test

  1. 1) DTC IS ACTIVE 
    NOTE: Diagnose and repair any Engine Coolant Temperature (ECT) sensor DTCs before proceeding with this test.
    NOTE: Inspect the ECT sensor and related PCM connector terminals for corrosion or damage.
    NOTE: Extremely cold ambient temperatures may cause this DTC to set.

    Turn the ignition on.

    With the scan tool, select View DTCs.

    Review DTC information.

    Is the Good Trip Counter greater than zero? 

    Yes 

    1. Refer to the *CHECKING FOR AN INTERMITTENT CONDITION Diagnostic Procedure.

    No 

    1. Go to  2).
  2. 2) LOW ENGINE COOLANT LEVEL 

    Ignition on, engine not running.

    WARNING: Allow the engine to cool before opening the cooling system. The system may be under pressure. Extreme burns or scalding may result. Failure to follow these instructions can result in personal injury or death.

    Inspect the cooling system for proper coolant level and condition.

    Were any problems found? 

    Yes 

    1. Inspect the vehicle for a coolant leak. Repair as necessary in accordance with the Service Information.
    2. Perform PCM VERIFICATION TEST .

    No 

    1. Go To  3).
  3. 3) THERMOSTAT 

    Ignition on, engine not running.

    NOTE: Allow the engine to cool to ambient temperature before proceeding with this test.

    Using the appropriate service information, determine the proper opening temperature of the thermostat.

    With a scan tool, read the ECT sensor value. If the engine was allowed to cool completely, the value should be approximately equal to the ambient temperature.

    Start the engine and allow it to reach operating temperature while monitoring the ECT sensor value. The sensor value change should be a smooth transition from start up to normal operating temperature. Monitor the actual coolant temperature with a thermometer.

    NOTE: As the engine warms up to operating temperature, the actual coolant temperature (thermometer reading) and the coolant temperature value on the scan tool should be relatively close. The thermostat should not open until the engine reaches the temperature specified in the Service Information.

    Does the thermostat open at the temperature specified in the Service Information? 

    Yes 

    1. Go to  4).

    No 

    1. Replace the thermostat in accordance with the Service Information.
    2. Perform PCM VERIFICATION TEST .
  4. 4) (K2) ECT 1 SIGNAL CIRCUIT SHORTED TO VOLTAGE 
    Fig 1: Measuring Voltage Of (K2) ECT 1 Signal Circuit In Engine Coolant Temperature Sensor 1 Harness Connector
    GC0054015Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the Engine Coolant Temperature Sensor 1 connector.

    Disconnect the Powertrain Control Module (PCM) connector.

    Turn the ignition on.

    Measure the voltage of the (K2) ECT 1 Signal circuit in the Engine Coolant Temperature Sensor 1 harness connector.

    Is there any voltage present? 

    Yes 

    1. Repair the (K2) ECT 1 Signal circuit for a short to voltage.
    2. Perform PCM VERIFICATION TEST .

    No 

    1. Go to  5).
  5. 5) (K2) ECT 1 SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 2: Checking ECT Sensor 1 Signal Circuit For Short To Ground
    GC0054016Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Measure the resistance between ground and the (K2) ECT 1 Signal circuit in the Engine Coolant Temperature Sensor 1 harness connector.

    Is the resistance above 100 ohms? 

    Yes 

    1. Go to  6).

    No 

    1. Repair the (K2) ECT 1 Signal circuit for a short to ground.
    2. Perform PCM VERIFICATION TEST .
  6. 6) (K2) ECT 1 SIGNAL CIRCUIT SHORTED TO (K900) SENSOR GROUND 1 CIRCUIT 
    Fig 3: Checking ECT Sensor 1 Signal Circuit For Short To Sensor Ground Circuit
    GC0054017Courtesy of CHRYSLER LLC

    Measure the resistance between the (K2) ECT 1 Signal circuit and the (K900) Sensor Ground 1 circuit in the Engine Coolant Temperature Sensor 1 harness connector.

    Is the resistance above 100 ohms? 

    Yes 

    1. Go to  7).

    No 

    1. Repair the (K2) ECT 1 Signal circuit for a short to the (K900) Sensor Ground 1 circuit.
    2. Perform PCM VERIFICATION TEST .
  7. 7) (K2) ECT 1 SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE 
    Fig 4: Checking ECT Sensor 1 Signal Circuit For Open Or High Resistance
    GC0054018Courtesy of CHRYSLER LLC

    Measure the resistance of the (K2) ECT 1 Signal circuit between the Engine Coolant Temperature Sensor 1 harness connector and the Powertrain Control Module (PCM) harness connector.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go to  8).

    No 

    1. Repair the (K2) ECT 1 Signal circuit for an open circuit or high resistance.
    2. Perform PCM VERIFICATION TEST .
  8. 8) (K900) SENSOR GROUND 1 CIRCUIT OPEN OR HIGH RESISTANCE 
    Fig 5: Checking ECT Sensor Ground Circuit For Open Or High Resistance
    GC0054019Courtesy of CHRYSLER LLC

    Measure the resistance of the (K900) Sensor Ground 1 circuit between the Engine Coolant Temperature Sensor 1 harness connector and the Powertrain Control Module (PCM) harness connector.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go to  9).

    No 

    1. Repair the (K900) Sensor Ground 1 for an open circuit or high resistance.
    2. Perform PCM VERIFICATION TEST .
  9. 9) ENGINE COOLANT TEMPERATURE SENSOR 1 
    Fig 6: Connecting Jumper Wire Between (K900) Sensor Ground Circuit And (K2) ECT 1 Signal Circuit In ECT Sensor 1 Harness Connector
    GC0054020Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Connect the Powertrain Control Module (PCM) connector.

    Connect a jumper wire between the (K900) Sensor Ground 1 circuit and the (K2) ECT 1 Signal circuit in the Engine Coolant Temperature Sensor 1 harness connector.

    Turn the ignition on.

    With the scan tool, read the Engine Coolant Temperature Sensor 1 signal voltage.

    Is the voltage below 1.0 volt with the jumper wire in place? 

    Yes 

    1. Replace the Engine Coolant Temperature Sensor 1 in accordance with the Service Information.
    2. Perform PCM VERIFICATION TEST .

    No 

    1. Go to  10).
  10. 10) POWERTRAIN CONTROL MODULE (PCM) 

    Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Engine Coolant Temperature Sensor 1 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 .
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