Truckers Report Jobs

Find Trucking Jobs

Company Driver Company Driver Dry Van Dry Van Flatbed Flatbed Refrigerated Refrigerated Specialized Specialized Owner Operator Owner Operator
More Trucking Job Searches ⌄ Fewer Trucking Job Searches
⌃

Low DEF light on but tank is full

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by DeSantisLogistics, Oct 18, 2019.

  1. Oct 18, 2019 #1
    DeSantisLogistics

    DeSantisLogistics Bobtail Member

    4
    1
    Apr 19, 2019
    0
    Hello all,

    I just had my DEF doser and gasket replaced in my Freightliner M2. On the way home from the shop I did a test drive. Shortly after picking the truck up it started an active regen and about 5 minutes later the low DEF indicator lamp came on. The gauge shows the truck is full and I also topped off the DEF fluid hoping that that would solve the problem but I have not had any luck. If anyone has had this issue before I would appreciate some direction as to how to proceed. Shop said it could be several different things and advised I do a little research and bring the truck back when I know more (thanks). They also scanned the truck again and there were not any fault codes at the time.

    Thank you.
     
    DeSantisLogistics, Oct 18, 2019
    DeSantisLogistics, Oct 18, 2019
    #1
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. Oct 18, 2019 #2
    McMahons Trucking

    McMahons Trucking Light Load Member

    274
    119
    Jul 4, 2018
    0
    Probably the sensor.
     
    McMahons Trucking, Oct 18, 2019
    McMahons Trucking, Oct 18, 2019
    #2
  4. Nov 14, 2019 #3
    jed222

    jed222 Bobtail Member

    11
    5
    Nov 14, 2019
    0
    Some def level sensors are a sliding float look in the tank see if you can see it and tits stuck down u may have to pull it out and free it up most likely crystals in tank making it stuck
     
    jed222, Nov 14, 2019
    jed222, Nov 14, 2019
    #3
    jammer910Z Thanks this.
  5. Nov 15, 2019 #4
    Goodysnap

    Goodysnap Road Train Member

    3,502
    8,384
    Jul 12, 2017
    0
    DEF gauge and indicator light or LED flashing on the gauge default to "E" is an standard for an active SCR related fault. Not necessarily a defect with the DEF level gauge itself or that the DEF is low.

    Need to hook up, could be many things.
     
    Goodysnap, Nov 15, 2019
    Goodysnap, Nov 15, 2019
    #4
    pushbroom and spsauerland Thank this.
  7. Nov 15, 2019 #5
    roshea

    roshea Road Train Member

    1,662
    1,745
    Sep 27, 2007
    Charlotte NC & Panama City FL
    0
    A low DEF warning or bad DEF quality fault is almost never the real problem, both of those things very rarely happen. NOX sensors can be faulty, as well a several other things. In my case if was DEF metering system needed to be replaced. Search TTR there and several discussions on this, look for replies from mhyn he is extremely knowledgeable on this topic, helped me tremendously.
     
    roshea, Nov 15, 2019
    roshea, Nov 15, 2019
    #5
    Dove, mhyn and spsauerland Thank this.
  8. Nov 16, 2019 #6
    Tx Countryboy

    Tx Countryboy Road Train Member

    1,969
    4,436
    Sep 18, 2019
    0
    Drain the tank & put fresh stuff in
     
    Tx Countryboy, Nov 16, 2019
    Tx Countryboy, Nov 16, 2019
    #6
  9. Dec 15, 2023 #8
    shaker179

    shaker179 Bobtail Member

    1
    0
    Jan 27, 2020
    0
    2018 m2 106 freightliner changed nox sensor now my DEF light won't go off. Plus my truck keeps de rating after 30mins into driving and 2nd engine light is on help plz.
     
    shaker179, Dec 15, 2023
    shaker179, Dec 15, 2023
    #8
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.