Need ecu pinout for 15 VNL 670 Coolant Level Sensor

Discussion in 'Volvo Forum' started by simonsocm, Jun 21, 2020.

  1. simonsocm

    simonsocm Bobtail Member

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    Aug 17, 2019
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    Just like the title states, I need to know what pins the coolant level sensor use on the ecu and if the ground is shared with other sensors.

    I've replaced the sensor and checked the wiring near the sensor. There's part of my engine harness that previously was rubbing on the ecu connector and I have a sneaking suspicion that my issue is stemming from right there.
     
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  3. Snailexpress

    Snailexpress Road Train Member

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    upload_2020-6-27_10-45-28.png

    There is float inside the expansion reservoir with magnet which triggers sensor when level is low. Try to rotate sensor 90 degree, sometime it's magnet position will set false signal.
     
  4. simonsocm

    simonsocm Bobtail Member

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    Thanks a ton! I didn't know the angled sensor trick but that may have been my issue. If it comes up again though then this picture will come in handy.





     
  5. kram1in

    kram1in Bobtail Member

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    remove the expansion tank. should hear the float move.
     
  6. simonsocm

    simonsocm Bobtail Member

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    I'll be replacing the expansion tank and hoses for it this week. That's not the issue but I've got a mild leak now too. I recently had this pop up again and unplug the sensor. Stop engine light still came on. So now I get to unplug the ecu and start chasing wires. Yay.
     
  7. Snailexpress

    Snailexpress Road Train Member

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    Unplug sensor and check with DMM what you have on the plug side and is sensor working or not? Disassemble the plug to check are wires crimped to the terminals and no corrosion.
     
  8. simonsocm

    simonsocm Bobtail Member

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    The issue isn't an open, it's an intermittent short. Unless I'm thinking incorrectly the float closes the circuit and then the dash shows extremely low coolant and a stop light. If I'm thinking correctly about it, then a paperclip in the plug would pull up a stop light constantly. I'll check that first and if that's the case then I may unplug the ecu and depin one of those wires for the meantime til I can figure it out.


     
    Snailexpress Thanks this.
  9. Snailexpress

    Snailexpress Road Train Member

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    You are on right troubleshooting patch. Remove reservoir from radiator top and check with ohmmeter sensor, flipping reservoir upside down and back. Note is sensor shortens when full or when empty. If I remember right, the normal (reservoir is full) sensor open.
    Did you check wire connection inside the plug? To disassemble plug you need special tool. https://www.amazon.com/MENKEY-Termi...5BFRRCE5WXN&psc=1&refRID=Y1AG8W05D5BFRRCE5WXN
     
  10. simonsocm

    simonsocm Bobtail Member

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    Well I tested another sensor, there's two spots that a magnet reacts to. Left alone it's at 2k ohm, on the higher mark it's at 6k ohm (add coolant mark I'm assuming), lower mark near the bottom of the sensor it pulls up 750 ohm. This is using a dirt cheap eBay sensor so I'm not 100% sure that is what it's supposed to be like. I think I'm just gonna slap a 4k ohm resistor in the plug for now to see if that'll get me by for now til I have another week off to troubleshoot it.


    BTW thanks for that link, I've got a Deutsch connector kit put not anything else so that'll help immensely.

     
  11. Snailexpress

    Snailexpress Road Train Member

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    Just be careful with tampering sensor. I had same problem with one of my past truck and was almost ready to bypass sensor. Low coolant signal was on/off but every time i was pulling over to check. Once it was really low because the lower hose was damaged. Can you imagine all consequences if i didn't stop or sensor bypassed.
     
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