DEF fluid level sensor issues

[USMC84-93]

I have a 2017 2500HD LT L5P with a "DEF EMPTY" issue which the tank is COMPLETELY FULL. WTFO? The DEF pump was just replaced 5 months ago and has been working just fine. No codes ... just "tank empty" message. It refuses to run or reset DEF because of the "tank empty" message.

 

[2004LB7]

Fluid level sensor, wire or connector

 

[USMC84-93]

No P02EE code, just WALK ERROR because of TANK EMPTY warning. Yes, I understand that is the level. I am ready to make it a CORK (like back in the day) instead of everything being electronic. I am so past the TECH that is CRIPPLING EVERYONES vehicles today. I want my floor and wing vents back to. My next test is to pull the pump AGAIN and run that level up and down to see if the system is detecting the change. Does anyone know the pin to test (and ohms or voltage) for that circuit? I suspect it runs through the DCM and then to the BCM or ECM? It is letting me REGEN (FASCINATING) but not do any other tests or resets because of the TANK EMPTY.

 

[2004LB7]

 

[USMC84-93]

THANK YOU SO MUCH!

 

[USMC84-93]

I am trying to work here and your burger image is killing the work on the truck mood. LOL On pin 13 I have 5v but on pin 14 there is 0v. I guess I am buying ANOTHER DEF pump.

 

[USMC84-93]

There is another smaller unit on the bottom of the DEF tank 11709610012, 7910056AH. What is this, please?

 

[2004LB7]

reductant quality sensor

 

[Chevy1925]

I have a 2017 2500HD LT L5P with a "DEF EMPTY" issue which the tank is COMPLETELY FULL. WTFO? The DEF pump was just replaced 5 months ago and has been working just fine. No codes ... just "tank empty" message. It refuses to run or reset DEF because of the "tank empty" message.

What dues the ecm show for a level on a scanner? In the reductant area for data using a scanner what does it show for a warning? Did you use a factory pump and sending unit or did you use an aftermarket back when you replace this?

 

[2004LB7]

Moved discussion about the fluid level sensor into it's own thread as it's not related to the original

 

[USMC84-93]

What dues the ecm show for a level on a scanner? In the reductant area for data using a scanner what does it show for a warning? Did you use a factory pump and sending unit or did you use an aftermarket back when you replace this?

Everything shows EMPTY. The only way it changes (to FULL) is it I apply 5v to pin 14 on the DEF Pump. But that still didn't reset the limited miles issue. While the DEF is showing flow rate and temperature, I can still perform a REGEN but not a quality test or pressure test. Reductant pressure is 72.516psi, pump speed is 2012, DEF differential pressure .054, reductant concentration correct.

 

[Chevy1925]

Let me know on the other 2 questions

 

[USMC84-93]

Let me know on the other 2 questions

I used an Amazon (liked like the OEM) (exact in every way) unit. GM has started playing DIRTY be superseding part numbers and then not pulling the bad parts OFF the market costing consumers far too much money. I did not replace the sending unit (just the pump). I am unfamiliar with the sending unit.

 

[USMC84-93]

I used an Amazon (liked like the OEM) (exact in every way) unit. GM has started playing DIRTY be superseding part numbers and then not pulling the bad parts OFF the market costing consumers far too much money. I did not replace the sending unit (just the pump). I am unfamiliar with the sending unit.

Would the sending unit be the injector?

 

[USMC84-93]

This truck is GHOST BUSTED. Another day another list of codes to chase.
P0672-00 Engine Control Module - Cylender 2 Glow Plug - Control Circuit
P06C6-00 Engine Control Module - Cylender 2 Glow Plug - Incorrect
P1339-00 Engine Control Module - Cylender 2 Glow Plug (Exceeded Learned Limit) This glow plug is reading 3v and the part is on order.
220EE-00 NOX Catalyst Efficiency - Below Threshold
U0422-71 Electronic Brake Control Module - Invalid Data
C0765-29 Body Control Module - Invalid Data
B1325-03 Radio Control Module - Low Voltage

And is still complaining about the limited mileage due to DEF Tank Empty.

 

[2004LB7]

Test continuity between level sensor connector and ECM connector

 

[USMC84-93]

Removed and tested the DEF Control Module (pins 13 = 5v and 14 0v not 5v). I jumpered pins 13 and 14 and the tank stated “FULL” but the limited driving distance did not reset. Since pin 14 needs to have 5v to tell the system that the tank is full apparently the NEW (5 month old DEF Pump is already bad). I will need to remove the pump to check that the level is not stuck and see if it changes when moving it up and down. But I will also need to check all the voltages on the circuit to ensure that there isn’t any other issues with the voltage either. Upon starting the truck the “FULL” message changed to “MALFUNCTION.” HOWEVER, this did reset our limited mileage error message from 71 miles before 45mph to 500 miles before 65mph.

 

[USMC84-93]

What is the rubber cover on the bottom of the DEF Pump? Is that a drain plug?

 

[2004LB7]

Removed and tested the DEF Control Module (pins 13 = 5v and 14 0v not 5v). I jumpered pins 13 and 14 and the tank stated “FULL” but the limited driving distance did not reset. Since pin 14 needs to have 5v to tell the system that the tank is full apparently the NEW (5 month old DEF Pump is already bad). I will need to remove the pump to check that the level is not stuck and see if it changes when moving it up and down. But I will also need to check all the voltages on the circuit to ensure that there isn’t any other issues with the voltage either. Upon starting the truck the “FULL” message changed to “MALFUNCTION.” HOWEVER, this did reset our limited mileage error message from 71 miles before 45mph to 500 miles before 65mph.

Looks like the line is good so it's a bad module. If you got an aftermarket one then no surprise there.

If you have other issues such as bad EGT or NOX sensors it may restrict running the reductant quality tests to clear the messages

 

[USMC84-93]

I am planning on replacing the NOX1, ECM, and glow plugs to start with and may order the BCM just in case too since it keeps coming up. I am also going to run a graph on the charging system to ensure that there isn't any over voltage from the alternator because the headlight plugs are scorched and some of the voltage readings are high (there and then gone). I really do appreciate the help. What's is the EGT (Exhaust Gas Temperature Sensor)? It's already past 275,000 miles (about time to replace EVERYTHING).