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Home >> Jeep >> 2005 >> Wrangler Rubicon, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 543 (Engine Controls - DTCS P0016 To P0118, Diagnostic Code Index, Pre-Diagnostic Troubleshooting, Intermittent Condition) >> Diagnosis And Testing >> P0116-Engine Coolant Temperature Sensor Circuit Performance >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
  1. 1)  ACTIVE DTC 

    Ignition on, engine not running.

    With a scan tool, read DTCs.

    Is the DTC active at this time? 

    Yes 

    1. Go To step  2).

    No 

    1. Refer to INTERMITTENT CONDITION .
    2. Perform POWERTRAIN VERIFICATION TEST .
  2. 2)  (K2) ECT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE  
    Fig 1: Checking ECT Signal Circuit Shorted to Battery Voltage
    GC0002664Courtesy of DAIMLERCHRYSLER CORP.

    Turn the ignition off.

    Disconnect the C2 PCM harness connector.

    Disconnect the ECT Sensor harness connector.

    NOTE: Visually inspect both the component and the PCM connectors. Look for damaged, partially broken wires, and backed out or corroded terminals.

    Ignition on, engine not running.

    Measure the voltage on the (K2) ECT Signal circuit in the ECT Sensor harness connector.

    Is the voltage above 0 volts? 

    Yes 

    1. Repair the short to battery voltage in the (K2) ECT Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go To step  3).
  3. 3)  ECT SENSOR VOLTAGE ABOVE 4.6 VOLTS 

    Turn the ignition off.

    Connect the C2 PCM harness connector.

    Ignition on, engine not running.

    With a scan tool, read the ECT voltage.

    Is the voltage above 4.6 volts? 

    Yes 

    1. Go To step  4).

    No 

    1. Go To step  7).
  4. 4)  ECT SENSOR 
    Fig 2: Checking ECT Sensor
    GC0002669Courtesy of DAIMLERCHRYSLER CORP.

    Connect a jumper wire between the (K2) ECT Signal circuit and the (K900) Sensor ground circuit in the ECT Sensor harness connector.

    With a scan tool, read the ECT voltage.

    Is the voltage below 1.0 volt with the jumper wire installed? 

    Yes 

    1. Replace the ECT Sensor.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go To step  5).
      NOTE: Remove the jumper wire before continuing.
  5. 5)  (K2) ECT SIGNAL CIRCUIT OPEN 
    Fig 3: Checking ECT Signal Circuit Open
    GC0002665Courtesy of DAIMLERCHRYSLER CORP.

    Turn the ignition off.

    Disconnect the C2 PCM harness connector.

    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 (K2) ECT Signal circuit from the ECT Sensor harness connector to the appropriate terminal of special tool #8815.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go To step  6).

    No 

    1. Repair the open in the (K2) ECT Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  6. 6)  (K900) SENSOR GROUND CIRCUIT OPEN  
    Fig 4: Checking ECT Sensor Ground Circuit
    GC0002666Courtesy of DAIMLERCHRYSLER CORP.

    Measure the resistance of the (K900) Sensor ground circuit from the ECT Sensor harness connector to the appropriate terminal of special tool #8815.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go To step  9).

    No 

    1. Repair the open in the (K900) Sensor ground circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  7. 7)  (K2) ECT SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 5: Checking ECT Sensor Signal Circuit For Short To Ground
    GC0002667Courtesy of DAIMLERCHRYSLER CORP.

    Turn the ignition off.

    Disconnect the C2 PCM harness connector.

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

    Is the resistance below 100 ohms? 

    Yes 

    1. Repair the short to ground in the (K2) ECT Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go To step  8).
  8. 8)  (K2) ECT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT 
    Fig 6: Checking ECT Sensor Signal Circuit For Short To Ground Circuit
    GC0002668Courtesy of DAIMLERCHRYSLER CORP.

    Measure the resistance between the (K2) ECT Signal circuit and the (K900) Sensor ground circuit in the ECT Sensor harness connector.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Repair the short between the (K900) Sensor ground circuit and the (K2) ECT Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go To step  9).
  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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