2018 L5P dpf pressure sensor 5 volt ref

[earnman]

i have a code p2452 i changed sensor still code comes back i checked voltage at sensor was 3.5 volt
i plugged back in and scanner says 0 psi and starts at .22 volts and drops to .16 volts..
how do i back check for the 5 volt reference
thanks for any input..

 

[mamumtsllc]

i have a code p2452 i changed sensor still code comes back i checked voltage at sensor was 3.5 volt
i plugged back in and scanner says 0 psi and starts at .22 volts and drops to .16 volts..
how do i back check for the 5 volt reference
thanks for any input..

Any other codes active? What other characteristics is the truck showing?

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[earnman]

p2455, p244a. but ithink because key on running and not when unplugged . i tested voltage when unplugged shows 5 volts and about 14 psi.at sensor i hook up scanner with unplugged 5 volts 14psi until i plug it in then voltage drops to .33 and zero psi. even with new sensor..i tried giving sensor 5 psi on pre dpf line did not change anything??

 

[earnman]

also dpf lines are clear not plugged i took them off no blockage in lines or dpf filter
i also put a white rag over tail pipe reved a few times no soot and no soot on tail pipe

 

[2004LB7]

Sounds like a bad connection, corroded or broken wire that is barely making a connection. With no load it will provide 5 volts. When loaded with the sensor the wire/connection can't support the load and the voltage drops

 

[earnman]

was a thought but all connections look great but what i thought i knew was is no psi you get no voltage with some pressure voltage goes up??
i am trying to trace backwards but at a loss were to start??

 

[2004LB7]

was a thought but all connections look great but what i thought i knew was is no psi you get no voltage with some pressure voltage goes up??
i am trying to trace backwards but at a loss were to start??

Should be the lower the pressure the lower the voltage. But remember it's a differential pressure sensor so it's the difference in pressure that adjusts the voltage.

You could test the ECM sees the voltage and pressure correctly by installing a potentiometer in place of the sensor.

But I think you should load test your line that feeds the sensor the 5V

 

[mamumtsllc]

Also need to know what other sensors share that 5v. It could be another sensor if not the wire that once plugged in the other sensor kills the voltage.

Ebp sensor on cummins and fords have ate my lunch before for that very scenario.

So I always try to find what sensor are common.


But I also agree on the wire/connection issue sounds more likely.

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[earnman]

how do i find what other sensors are on that circuit?

 

[2004LB7]

If you're getting 5 V with the DPF pressure sensor unplugged, it's probably not any other sensor. I'd still be suspicious of the replacement sensor you tried

I'd put a 20 ohm resistor across the 5V and ground and measure the voltage. That should put a 250 mA load on it which your 5V supply should be able to do. It should maintain at least 4.5V with a load. A 10 ohm resistor will draw 500 mA. You can try it, but not sure the supply cna do that much and might shut down. If it can hold then it's likely your differential sensor

 

[earnman]

i do have some resistors gotta look for them but if i remember are higher..

 

[earnman]

replacement sensor i put in is a oem gm sensor

 

[Chevy1925]

View attachment P2455.pdf

Follow the flow chart, see what you come up with.

 

[kidturbo]

For testing a 5v Ref related circuits, best tool is any old simple potentiometer. 5v Ref goes in on one side, Gnd on the other, signal out is center. This allows you to sweep the 0-5v scale easily with one hand, while holding a scan tool in the other..

However, as listed above, follow the diagnostics chart first, and verify you have one of those wires with good 5v going to the sensor. If all good there, then replace any sensor with a POT's, and verify signal moves on the scan tool. If not, likely have a break or short to hot in the Signal wire somewhere.

That's how I would approach it.

 

[earnman]

i only got codevp2455 when engine was running and not plugged in..i tested ,,,.. unplugged other sensors i thought was in 5v reference circuits.. no change just keep comming nup with codes p2452 and p2454 every time??

 

[Chevy1925]

The flow chart covers those codes…

 

[earnman]

you have a flow chart for p2454? i looked at it triesd to follow but did not lead me to were i need it ..dead end..
could not do p2454 not a option only high lighted p2455??i have a appt the 17th ..$180 a hour.. sad i was a mechanic for 40 years
i cannot find a good schematic i need for ecm break out.. with out spending lots of money for that...

 

[earnman]

i need a 5 v reference on that circuit ecm pin out

 

[earnman]

to see what sensors are bon that circuit

 

[Chevy1925]

I dont know how more clear that can be. Goes on about the code further down as well.

Spend 20 bucks and get all the diagrams you need for a month

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