Sentra 2008

Engine Coolant Temperature Sensor

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Location



Specific to:

Nissan Sentra 2007-2012



Click image to see an enlarged view

Fig. The ECT is in the water outlet assembly near the upper radiator hose connection.

Operation



CIS Circuit Testing

Specific to:

Nissan Sentra 2007-2012

Use a suitable scan tool or a Graphing Multi-Meter (GMM) in order to view the CMP data.  

CIS Sensor logic is based on alternating lines of magnetic flux which generate a digital ON/OFF signal to the PCM, and are based position of the camshaft.

Verify that the engine timing components (timing belt, timing chain, or timing gears) are properly installed, and that there is no foreign material obstructing the path between the reluctor and the CIS sensor. If any engine mechanical faults are evident, locate and repair as required before continuing.  

A Digital Volt-Ohm Meter (DVOM) may be used to verify the condition of the wiring: additional information may be acquired by taking measurements at the sensor connector as well as the PCM connector. If significant resistance is measured (greater than 5 ohms) is measured, check the wiring harness and connections for corrosion, poor pin connections, or damaged wires.

If all engine wiring and pin connections are confirmed, disconnect the CIS Sensor to verify the signal with a GMM, and verify PCM communication before replacing the CIS Sensor.

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Fig. CIS Sensor Range Chart

CIS Sensor Strategy

Specific to:

Nissan Sentra 2007-2012

The CIS Sensor provides a digital input signal to the Powertrain Control Module (PCM) for a number of engine control system calculations. The CIS signal is compared with the Crankshaft Position (CKP) sensor (CKP) and Vehicle Speed Sensor (VSS) for measured operating conditions, and the Pulse Width Modulation pattern is used by the Powertrain Control Module (PCM) to calculate ignition timing, firing order, fuel injector timing, and misfire diagnostics.

Related Diagnostic Trouble Codes

Specific to:

Nissan Sentra 2007-2012



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Fig. Related Diagnostic Trouble Codes

Connection & Wiring Diagnosis

Specific to:

Nissan Sentra 2007-2012

Refer to the Electrical Wiring Diagram for component and connector locations, connector views, and circuit-specific information.  

Many intermittent open or short circuits may be caused by wiring harness and connector movement due to vibration, engine torque, bumps and rough pavement, etc.

  1. Test the wiring harness and connectors by performing the following tests:

    Move the related connectors and wiring while monitoring the appropriate scan tool data.
     
    Move the related connectors and wiring with the component commanded ON and OFF. Using a suitable the scan tool, observe the component operation.
     
    With the engine running, move the related connectors and wiring while monitoring component operation.
     
    If harness or connector movement affects the data displayed, the component and system operation, or the engine operation, inspect and repair the harness or connections as necessary.
     

  2.  
  3. Test the connector terminal pins and/or wiring by performing the following tests:

    Inspect for incorrect mating of the connector halves, or terminals not fully seated in the connector body.
     
    Inspect for improperly formed or damaged terminals and test for incorrect terminal tension.
     
    Inspect for poor terminal to wire connections including terminals crimped over insulation. This requires removing the terminal from the connector body.
     
    Inspect for corrosion or water intrusion. Pierced or damaged insulation can allow moisture to enter the wiring. The conductor can corrode inside the insulation with little visible evidence. Look for swollen and/or brittle sections of wire in the suspect circuits.
     
    Inspect for wires that are broken inside the insulation by gently pulling on suspect sections of wiring.
     

  4.  

Removal & Installation



Specific to:

Nissan Sentra 2007-2012

  1. With the ignition switch OFF , unplug the sensor connector.
  2.  
  3. Unscrew the sensor.
  4.  
  5. During installation, use a new O-ring and make sure the sensor is clean.
  6.  

Testing



Specific to:

Nissan Sentra 2007-2012

  1. Turn ignition switch ON and wait at least 5 seconds.
  2.  
  3. Check DTC. Is DTC detected-
  4.  
  5. Turn the ignition switch OFF and unplug the wiring harness from the sensor.
  6.  
  7. Turn the ignition switch ON and check for 5 volts between terminal 1 on the wiring harness connector and chassis ground. If there is no voltage or if there is voltage at both terminals, check the wiring harness for damage that might cause open or short circuits.
  8.  
  9. Check for voltage across both terminals on the wiring harness connector. If there is no voltage, check the wiring harness for damage. The ground is provided by the ECM.
    WARNING
    Connect the voltmeter ground probe to engine or chassis ground. Do not test circuits with the meter connected to the negative battery terminal or the ECM may be damaged.

  10.  
  11. Turn ignition switch OFF .
  12.  
  13. Check the resistance across sensor terminals 1 and 2. Compare your reading with the table below. If resistance is incorrect, replace the sensor.

    Click image to see an enlarged view

    Fig. Engine coolant temperature sensor resistance

  14.  

 
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