Def Codes And Gauge On Empty

Barry Mechanic Virginia Posted   Latest   Edited  
Resolved
Electrical
Heavy Duty
2017 Freightliner M2 106 6.7L (ISB 6.7)
P4677
P4572
P3868
P3714
Check Engine Light On Def Codes Pressent For Tank Sensor Assembly

Hey guys have this truck that came in on the hook because a strap fell off the rollback bed got tangeld up in the driveshaft and ripped all electrical air and hydrualic lines out from under the truck after two months of waiting we got the proper wrirng harnesses hoes ect I didn't do the work in the begining I got called in to figure out the def codes I have checked all connections ohmed out all wires to the def tank sensor assembly chcked for voltage at the 4pin connector at the tank sensor and have on pin1 2.55 volts pin2 2.44 volts pin3 12.10 volts and pin4 is the ground according to what I can find these are the proper voltages for this system the ground ohms out to 0.3 the tank sensor assembly has been replaced and the results are the same have same codes as before so im starting to think that maybe we got a faulty in tank sensor if anyone knows something else to try let me know I dont know what else to check

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Glenn Owner/Technician
Texas
Glenn
 

Hi Barry, Disconnect the batteries and attach the positive and negative cables to each other away from the batteries for a few minutes to clear all KAM and it will reset the ECM programming. After that reconnect and test run and retest the system. I have had some success using this method in the past.

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Barry Mechanic
Virginia
Barry
 

Tryed that this morning still have the same result like I said im leaning to the new sensor being bad out of the box everything I have checked is telling me that at least I hope it is sensor is $900 if im wrong.

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Adam Technician
Massachusetts
Adam
 

Pin 1 and 2 are your data bus. With battery disconnected check for resistance between the two. You should have 60 ohms, if you do not you have a network issue. If that checks out and you have good power to pins 3 and 4 (check under load) than you may have a bad sensor.

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Barry Mechanic
Virginia
Barry
 

Have 57.2 omhs across pins 1 and 2 I'm leaning more and more to the in tank sensor

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Adam Technician
Massachusetts
Adam
 

Sounds like it

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Christopher Technician
Saskatchewan
Christopher
 

Voltage on the CAN wiring is one thing but is the wave form correct? I have seen multiple DEF quality/level smart sensors corrupt the network. You may want to check that on a scope

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Rex Technical Support Specialist
Ohio
Rex
   

Major quality AND availability issues with the quality sensors. So bad the EPA has issued an emergency waiver to take these out of the circuit thru programing. A Cummins authorized location has to do it. I believe no charge to the customer. Most eligible ESNs are listed on Quckserve, although as of a week ago ESNs were still being added. This waiver only applies if the sensor is unavailable…

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Barry Mechanic
Virginia
Barry
 

Just a question has anyone gotten a new def tank sensor that was bad straight out of the box???

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Katelyn Technician
Georgia
Katelyn
 

Yes. Freightliner, Daimler, and Detroit have all been problematic with bad parts straight from the box since the very beginning of supply issue days.

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Christopher Technician
Saskatchewan
Christopher
 

Yes I have seen them bad out of the box , that being said usually there is something else, like green network wiring

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Barry Mechanic
Virginia
Barry Update
 

Well guys tryed the sensor to no avail everything that I have checked has told me that the in tank sensor was bad only thing I cant do is scope the data lines shop doesen't have a scope does anyone have any wiring diagrams on this truck for the def system I cant find anything on the web and freightliner is no help just to check pin location and other wiring to the def tank sensor and def pump…

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Barry Mechanic
Virginia
Barry Resolution
 

Still working on the problem talking with freightliner about the wiring harness they sold us hope to figure out something soon thanks to all for the advice

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