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Mike, volvo Tech
Mike, volvo Tech, Technician
Category: Volvo
Satisfied Customers: 1303
Experience:  20+ yrs volvo technician, Ase A1-A8, L1, A/C certified
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How do I test a 1993 volvo crank shaft position sensor?

Customer Question

How do I test a 1993 volvo crank shaft position sensor?
Submitted: 6 years ago.
Category: Volvo
Expert:  Jerry replied 6 years ago.

Hello and welcome to Just answer.com, Super mechanic here. About your vehicle.

 

Which series is it?

Customer: replied 6 years ago.
1993 940 2.3 non turbo
Expert:  Jerry replied 6 years ago.

I have this,

 

TESTING PROCEDURE :

 

graphic

 

  • Turn ignition OFF.
  • Access ignition ECM by removing the panel under left hand side of instrument panel.
  • Remove ECM connector by pushing out the catch and folding out the wire cluster.
  • Check ignition ECM ground connections at intake manifold. They should make good contact.
  •  

     

    graphic

     

    1. Remove connector protective sleeve.

    IMPORTANT :

    • Never check connections from the front. Connectors can get damaged and worsen the problem.
    • Check connections through the holes in the connector.
    • Connection pin numbers are printed on the connector side.

     

     

     

    graphic

     

     

    1. Check that terminal contacts have been pushed down evenly in connector.
    2. If any connectors have been pushed down to far, poor connection may result.

     

    graphic

     

    1. Check main power supply by connecting a voltmeter between pin 5 in ECM connector and ground.

    Reading: approx. 12 volts

    1. If no voltage registers, check wire between ECM and fuse-box located behind the center console ash tray. Check fuse #1, #3 and wiring to battery (incl. battery terminals). Repair as necessary.

     

     

    graphic

     

     

  • Check crankshaft position/speed sensor by connecting an ohmmeter between ECM connector pin 10 and ECM connector pin 23. Reading should be: Sensor(NNN) NNN-NNNN5 (older type) -- 240 ±25 ohms @ 20°C Sensor(NNN) NNN-NNNN8 (newer type) or(NNN) NNN-NNNN5 with white dot -- 170 ±30 ohms @ 20°C
  • If value is incorrect, check wiring. If wiring is O.K., replace crankshaft position/speed sensor.
  •  

     

     

    graphic

     

  • Check that screening is connected to pin 11. Fix if necessary.
  • After testing, disconnect all test equipment, reconnect all connectors (including the ECM connector) and remount all panels.
  •  

    Customer: replied 6 years ago.
    I did test on crank position sensor and voltage to ecm as per info you sent and everything checks out . Can you help with next step? thanks much Larry
    Expert:  Jerry replied 6 years ago.

    The best way to diagnos that system would be with a scan tool. However, they did use a couple of different ignition setups in that year. The "Bosch" system would have a power stage type of module for the ignition. See if there is a part under the hood that looks like this. You will have to remove the air filter top housing to see. Also, that the distributor is turning when you crank the engine.

     

    TESTING PROCEDURE :

    NOTE: While trouble shooting, always check the wiring, fuses and connectors for good condition and routing. Use the wiring diagrams found in CHASSIS ELECTRICAL DIAGRAMS to supplement your testing efforts.

     

     

    graphic

    Turn ignition OFF and access the power stage by removing the air filter housing top.

     

     

     

    The "Bendix" type will be built into the ignition ECU and will be,

    The ignition system control unit is located under driver side dash board.

     

    It will look like this,

     

    graphic

    Customer: replied 6 years ago.
    From what I can tell this system is REX-1. ECM is Bendix. Power stage and coil combo are mounted on strut tower on bracket, drivers side of car, one three wire connector and one two wire connector.

    Terminal A of power stage three way connector has 11 volts while cranking engine.

    Checked for poor ground. From terminal B of three way connector to ground 0.1 ohm

    Checked terminal A of two way connector, Same.

    Thank you, Larry

    Expert:  Jerry replied 6 years ago.
    Are you getting any trouble codes?
    Customer: replied 6 years ago.
    Trouble code 1-1-1 no fault found. Rotor is turning with engine.

    thanks, Larry
    Expert:  Jerry replied 6 years ago.

    That's all the information that I have on it. Let me opt out and we can relist the case to see if there may be another expert who may have more insight as to what it may be. Thank you for your patience.

    Expert:  Mike, volvo Tech replied 6 years ago.
    when you checked for codes were you in pin 6 of the socket? pin 2 is the F.I. and pin 6 is the ignition system. get back to me on that and I will have some more information for you. Mike
    Mike, volvo Tech, Technician
    Category: Volvo
    Satisfied Customers: 1303
    Experience: 20+ yrs volvo technician, Ase A1-A8, L1, A/C certified
    Mike, volvo Tech and 7 other Volvo Specialists are ready to help you
    Expert:  Mike, volvo Tech replied 6 years ago.
    connector a volt meter to terminal "B" on the 2 pin connector and ground. cranking the motor you should have at least 250mv it that is correct needs a new coil/power stage unit. I have seen these fail on several cars. what was you resisatance reading of the crank sensor across terminal 1 and 2 on the 3 pin connector at the firewall for the crank sensor?
    Customer: replied 6 years ago.
    connected to #6 in socket.

    connected voltmeter to term B in two pin connector to ground. cranked engine shows approximate 495 Mv. Motor started.


    Now where do we go?   No doubt it will fail again.


    Thanks for help, Larry
    Expert:  Mike, volvo Tech replied 6 years ago.
    I would replace the coil/power stage assembly. they can be intermitent. did you have a code in pin #6?
    Customer: replied 6 years ago.
    Code in pin #6 was 1-1-1
    Expert:  Mike, volvo Tech replied 6 years ago.
    No codes. I would suggest replacing the coil assembly. that is what I have seen fail other than the crank sesnor.
    Customer: replied 6 years ago.
    Did you receive your payment?
    Customer: replied 6 years ago.
    Did you get your payment?

    Larry
    Expert:  Jerry replied 6 years ago.
    I see the accept on there, I'm sure he got it, thanks
    Expert:  Mike, volvo Tech replied 6 years ago.
    I got it thanks Mike

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