Altima 2007-2009

Crankshaft Position Sensor

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Location



2.5L Engine

Specific to:

Nissan Altima 2007-2008

Refer to the accompanying illustration for sensor location.

Click image to see an enlarged view

Fig. The Crankshaft Position (CKP) sensor is located on the oil pan-2.5L engine

3.5L Engine

Specific to:

Nissan Altima 2007-2008

Refer to the accompanying illustration for sensor location.

Click image to see an enlarged view

Fig. The Crankshaft Position (CKP) sensor is on the flywheel end of the block below the front cylinder head (manual transaxle model shown, automatic similar)-3.5L engine

Operation



Specific to:

Nissan Altima 2007-2008

The Crankshaft Position (CKP) sensor (POS) is located on the oil pan facing the gear teeth of the signal plate on the crankshaft (inside the engine block). It detects crankshaft revolution and position. The sensor consists of a permanent magnet and Hall IC. When the engine is running, the gaps in the teeth cause the magnetic field near the sensor to change. Due to the changing magnetic field, the voltage from the sensor changes. The ECM receives the voltage signal and detects the fluctuation of the engine revolution.

Specific to:

Nissan Altima 2009-2010

The Crankshaft Position (CKP) Sensor is a permanent magnet output coil device that monitors the speed and position of the crankshaft. A reluctor is attached directly to the crankshaft, and is used to generate a constant signal as it passes the CKP sensor magnetic coil. The CKP Sensor utilizes system voltage (12 volts DC), or reference voltage (5 volts DC) to generate a digital output signal to the PCM that is based upon a 0.5 volt AC reference. The alternating magnetic field is used by the sensor output electronics to produce a digital pulse. The CKP sensor returns a digital ON/OFF signal pulse during each revolution of the crankshaft, with a momentary signal interrupt for the top dead center (TDC) position of the #1 cylinder. The Pulse Width Modulation pattern is used by the Powertrain Control Module (PCM) to calculate ignition timing, fuel injector timing, misfire diagnostics, and the tachometer display.

Removal & Installation



Specific to:

Nissan Altima 2007-2008

  1. Unplug the connector.
  2.  
  3. Remove the bolt to remove the sensor.
  4.  
  5. During installation, use a new O-ring and make sure the sensor is clean and free of metal filings on the magnet end.

    Click image to see an enlarged view

    Fig. The Crankshaft Position (CKP) sensor is located on the oil pan-2.5L engine



    Click image to see an enlarged view

    Fig. The Crankshaft Position (CKP) sensor is on the flywheel end of the block below the front cylinder head (manual transaxle model shown, automatic similar)-3.5L engine

  6.  

Specific to:

Nissan Altima 2009-2010

  1. Turn ignition switch OFF.
  2.  
  3. Loosen the fixing bolt of the sensor.
  4.  
  5. Disconnect crankshaft position sensor (POS) harness connector.
  6.  
  7. Remove the sensor.
  8.  
  9. Installation is the reverse of removal.
  10.  

Testing



Specific to:

Nissan Altima 2007-2008

These procedures will test for:



The crankshaft position sensor signal is not detected by the ECM during the first few seconds of engine cranking.
 
The proper pulse signal from the crankshaft position sensor is not sent to ECM while the engine is running.
 
The crankshaft position sensor signal is not in the normal pattern during engine running.
 

  1. Turn ignition switch OFF and wait at least 10 seconds before going to the next step.
  2.  
  3. Confirm that battery voltage is more than 10.5V with ignition switch ON .
  4.  
  5. Start engine and let it idle for at least 5 seconds. If engine does not start, crank engine for at least 2 seconds.
  6.  
  7. If the engine starts and 1st trip DTC is not detected, maintain engine speed at more than 800 rpm for at least 5 seconds. If the DTC is still not detected, the sensor is functioning properly.
  8.  
  9. If the engine will not start and/or if the DTC is detected, turn ignition switch OFF and unplug the wiring harness at the sensor.
  10.  
  11. Turn the ignition switch ON and check for 5 volts at terminal 1 on the wiring harness connector. If there is voltage at any other terminal, check the wiring harness for damage that might cause short circuits.
  12.  
  13. Check for continuity to ground at terminal 3 on the wiring harness connector. If there is no ground, 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.

  14.  
  15. Turn ignition switch OFF .
  16.  
  17. Check the continuity between terminal 2 of the wiring harness connector and ECM harness connector.
  18.  
  19. To test the sensor itself, check continuity between any two terminals on the sensor connector. There should be measurable resistance, not zero or infinite resistance.
  20.  

Specific to:

Nissan Altima 2009-2010


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

CKP Circuit Testing

Specific to:

Nissan Altima 2009-2010

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

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

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 CKP 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), 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 CKP Sensor to verify the signal with a GMM, and verify PCM communication before replacing the CKP Sensor.

Click image to see an enlarged view

Fig. CKP Sensor Range Chart

CKP Sensor Strategy

Specific to:

Nissan Altima 2009-2010

The CKP Sensor provides a digital input signal to the Powertrain Control Module (PCM) for a number of engine control system calculations. The CKP signal is compared with the Camshaft Position Sensor (CMP) 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, fuel injector timing, misfire diagnostics, and the tachometer display.

Connection & Wiring Diagnosis

Specific to:

Nissan Altima 2009-2010

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.  

Related Diagnostic Trouble Codes

Specific to:

Nissan Altima 2009-2010



Click image to see an enlarged view

Fig. Related Diagnostic Trouble Codes

 
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