GM Corsica/Beretta 1988-1996 Repair Guide

Oil Pressure Sender

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OPERATION



The oil pressure sender relays to the dash gauge the oil pressure in the engine.

TESTING



  1. To test the normally closed oil lamp circuit, disengage the locking connector and measure the resistance between the switch terminal (terminal for the wire to the warning lamp) and the metal housing. The ohmmeter should read 0 ohms.
  2.  
  3. To test the sending unit, measure the resistance between the sending unit terminal and the metal housing. The ohmmeter should read an open circuit (infinite resistance).
  4.  
  5. Start the engine.
  6.  
  7. Once again, test each terminal against the metal housing:
    1. The oil switch terminal-to-housing circuit should read an open circuit if there is oil pressure present.
    2.  
    3. The sending unit-to-housing circuit should read between 15-80 ohms, depending on the engine speed, oil temperature and oil viscosity.
    4.  

  8.  
  9. To test the oil pressure sender only, rev the engine and watch the ohms reading, which should fluctuate slightly (within the range of 15-80 ohms) as rpm increases.
  10.  
  11. If the above results were not obtained, replace the sending unit/switch with a new one.
  12.  

REMOVAL & INSTALLATION



See Figures 1, 2 and 3



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Fig. Fig. 1: Oil pressure switch location - 1990 2.3L engine without ABS shown



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Fig. Fig. 2: Oil pressure switch location - 1990 2.3L engine with ABS shown



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Fig. Fig. 3: Oil pressure switch location - 1990 3.1L engine shown

  1. Remove the air cleaner assembly.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Raise and safely support the vehicle.
  6.  
  7. Position a suitable drain pan under the switch.
  8.  
  9. If the vehicle is equipped with a gauge package (large sensor assembly) and does not have and oil cooler, drain the engine oil, then remove the oil filter.
  10.  
  11. Detach the sensor electrical connector.
  12.  
  13. Remove the sensor.
  14.  

To install:
  1. Coat the first two or three threads with sealer. Install the sensor and tighten until snug. Engage the electrical lead.
  2.  
  3. If removed, install the oil filter.
  4.  
  5. Carefully lower the vehicle.
  6.  
  7. Connect the negative battery cable and fill the engine with oil.
  8.  

 
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