Altima 2007-2009

Camshaft 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 Camshaft Position (CMP) sensor is located on top of the engine at the flywheel end-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 Camshaft Position (CMP) sensors are located on top of each rocker cover at the flywheel end (front cylinder bank shown)-3.5L engine

Operation



Specific to:

Nissan Altima 2007-2008

The Camshaft Position (CMP) sensor (PHASE) senses the rotation and position of the camshaft to identify the position of each piston. If the crankshaft position sensor (POS) becomes inoperative, the camshaft position sensor (PHASE) takes over various controls utilizing timing of cylinder identification signals. The sensor consists of a permanent magnet and Hall IC. When the engine is running, the high and low parts of the teeth cause the gap with the sensor to change. The changing gap causes the magnetic field near the sensor to change. Due to the changing magnetic field, the voltage from the sensor changes. The ECM receives the signals as shown in the figure.

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Fig. Camshaft position sensor signal schematic

Specific to:

Nissan Altima 2009-2010

The Camshaft Position (CMP) Sensor is a permanent magnet output coil device that operates within a 5 volt DC reference range, and monitors the speed and position of the camshaft. A reluctor is attached directly to the camshaft, and is used to generate a digital signal as it passes the magnetic coil; the alternating lines of magnetic flux are used by the sensor to produce a digital pulse. The CMP signal is used by the Powertrain Control Module (PCM) to calculate ignition timing, firing order, fuel injector timing, and misfire diagnostics.

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 Camshaft Position (CMP) sensor is located on top of the engine at the flywheel end-2.5L engine



    Click image to see an enlarged view

    Fig. The Camshaft Position (CMP) sensors are located on top of each rocker cover at the flywheel end (front cylinder bank shown)-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 camshaft position sensor (PHASE) harness connector.
  6.  
  7. Remove the sensor.
  8.  
  9. Installation is the reverse of removal.
  10.  

Testing



Specific to:

Nissan Altima 2007-2008


NOTE
If DTC P0340 is displayed with DTC P0643 (sensor power circuit), first perform the trouble diagnosis for DTC P0643.

These procedures will test for:



The cylinder No. signal is not sent to ECM for the first few seconds during engine cranking.
 
The cylinder No. signal is not sent to ECM during engine running.
 
The cylinder No. 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.

CMP Circuit Testing

Specific to:

Nissan Altima 2009-2010

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

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

Click image to see an enlarged view

Fig. CMP Sensor Range Chart

CMP Sensor Strategy

Specific to:

Nissan Altima 2009-2010

The CMP Sensor provides a digital input signal to the Powertrain Control Module (PCM) for a number of engine control system calculations. The CMP signal is compared with the Crankshaft Position 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.

CMP Sensor feedback patterns vary according to the reluctor configuration and PCM logic. While most models use a single tooth for Top Dead Center (TDC), others may use multiple reluctor teeth for additional positions of camshaft rotation, which may include one per cylinder, or 0°,90°, 180°, and 270° respectively.

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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