Audi Cars 1999-05

Crankshaft Position Sensor

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The crankshaft position sensor on the distributorless ignition system on the side of the engine block, near the flywheel. This sensor provides a signal to the ECM regarding the speed and position of the crankshaft.

The crankshaft position sensor is an essential input for the ECM to determine ignition timing. For additional information, please refer to the following topic(s): Driveability and Emission Controls, Crankshaft Position Sensor.

Operation



The crankshaft position sensor detects gaps in the sensor ring corresponding to TDC of each cylinder. The sensor uses a permanent magnet, core and coil. The changing gap causes the magnetic field near the sensor to change. This in turn varies the voltage signal to the ECM. The ECM uses the signals for ignition timing and fuel synchronization.

Removal & Installation



  1. Disconnect the electrical connector from the sensor.
  2.  
  3. Remove the crankshaft sensor retaining bolt and remove the sensor.
  4.  
  5. Replace the O-ring and lightly lubricate it with clean engine oil.
  6.  
  7. Installation is reverse of removal.
  8.  

Testing



2.8L
  1. Disconnect the electrical harness connector.
  2.  
  3. Switch the DMM to its resistance range and connect it between the CKP sensor connector terminals 1 and 2 , using jumper wires from VW 1594 test kit. The DMM should show approximately 1,000 ohms.
  4.  
  5. If the specified value is not obtained, replace the crankshaft position sensor.
  6.  
  7. If the specified value is obtained, connect the DMM between terminal 1 and 3 (GND), then between terminals 2 and 3 (GND). The DMM should show infinite ohms (open).
  8.  
  9. If the specified value is not obtained, replace the crankshaft position sensor.
  10.  
  11. If the specified value is obtained, check the wiring for continuity or short between crankshaft position sensor and ECM, using a wiring diagram.
  12.  
  13. Connect a VAG 1598/19 test box to the ECM harness connector.
  14.  
  15. Check the CKP sensor shielding for continuity by connecting a DMM between terminal 3 and engine ground (GND). The DMM should show a maximum of 1 ohm.
  16.  
  17. Check the wiring for continuity between the CKP sensor connector terminal 1 and the test box socket A9 , then between the CKP sensor connector terminal 2 and test box socket A10 . There should be a maximum of 1 ohm.
  18.  
  19. If the specified values are not obtained, check and eliminate any short or open circuits in the wiring.
  20.  
  21. If the wiring is OK, replace ECM.
  22.  

 
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