Def emissions problem

[Chris142]

Had to tow a peterbilt back to the yard last night. The DEF system has a problem. The level sender has failed so the ecm thinks that the truck is out of DEF.

The ecm shut the truck down thinking it's out but the tank is full.

Now the good part. The part is on back order with no known delivery date!

My boss is demanding that I get the truck usable. I can't find any info on how to bypass the level sensor. Not trying to defeat the emissions system. Just the sender and keep the tank full untill parts become available.

 

[RooflessVW]

Not much to be done imho unless you can get a resistance value from a known-good unit. Then you should be able to spoof it into thinking it's full.

 

[wpod]

The cost of having a Dead semi is staggering to a company. Maybe if there is a dealer you could do a face to face with one of there techs. Maybe there would be help there.

 

[Danno]

Had to tow a peterbilt back to the yard last night. The DEF system has a problem. The level sender has failed so the ecm thinks that the truck is out of DEF.

The ecm shut the truck down thinking it's out but the tank is full.

Now the good part. The part is on back order with no known delivery date!

My boss is demanding that I get the truck usable. I can't find any info on how to bypass the level sensor. Not trying to defeat the emissions system. Just the sender and keep the tank full untill parts become available.

I find that all the time on dealer parts, back ordered forever.
If you have a part number, try to source it anywhere on the internet.
I've had good success on eBay. Might be different with a Class 8 tractor, but worth a try imo.

 

[Chris142]

I find that all the time on dealer parts, back ordered forever.
If you have a part number, try to source it anywhere on the internet.
I've had good success on eBay. Might be different with a Class 8 tractor, but worth a try imo.

Please allow 4-5 weeks! LoL

 

[Lyman]

Find out what the resistance is supposed to be and go down to your local electronics store. Trick it into thinking it's full.

 

[Danno]

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[tnt_motorsports]

I like the internet suggestion but another option, could you see if there is a used one of a wreck? The supply chain is in turmoil right now with the shortage of workers and especially OTR truckers. Shipping times and rates are going up because of supply and demand.

just my $0.02

 

[Jetronic]

Not much to be done imho unless you can get a resistance value from a known-good unit. Then you should be able to spoof it into thinking it's full.

Could be sending a PWM signal

 

[RooflessVW]

Could be sending a PWM signal

Didn't even occur to me. This is probably more likely, in an effort to defeat easy spoofs.

 

[Lyman]

Could be sending a PWM signal

It's just a simple float type sending unit. Would one of those generate such a signal? I'd guess no.

 

[Jetronic]

the one listed above measures def concentration, so not a float...

 

[dlundblad]

My new favorite word is “agonizing”. This situation is fitting.

 

[Dave Hess]

Is this the same jerk boss that’s constantly harassing you ?

Just tell him it’s back ordered with no ETA....

 

[Jetronic]

And tell him to put some sensitive stuff like that in stock to avoid this in future. You can get rid of some 20 year old filters if there's no room.

 

[dlundblad]

Is this the same jerk boss that’s constantly harassing you ?

Just tell him it’s back ordered with no ETA....

Yes.

No way to fix and he needs to rent something until it can be fixed. That or get something a little older without emissions stuff.

 

[zzyzzx]

How many wires on the connector end? If only 2, then it might work with either an open circuit (you unplug it) or if you short it if it's just a switch. Post a schematic of the circuit here for our review.

 

[Chris142]

Yes.

No way to fix and he needs to rent something until it can be fixed. That or get something a little older without emissions stuff.

Can't. We are in California.

 

[Chris142]

How many wires on the connector end? If only 2, then it might work with either an open circuit (you unplug it) or if you short it if it's just a switch. Post a schematic of the circuit here for our review.

4

 

[zzyzzx]

A schematic would still be nice. The 4 pin connector suggests that it's more than just a simple switch. I would remove the sensor and clean it out real good and ohm out all the pins to each other.