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Discussion Starter · #1 ·
Hey guys my check engine light is on and the code is for the purge canister solenoid circuit. Turns out fuse is blowing. After replacing fuse check engine light will go away, but returns after at most a week.

So my question is does anyone have a schematic for this circuit or know of a common reason for this circuit to short. Thanks in advance for any help.
 

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What is the code from the PCM? P1495 (from my Haynes manual) indicates
"leak detection pump solenoid circuit fault (short or open circuit)".

This is part of the EVAPorative canister system located ahead of the fuel tank.

The purge control solenoid on the intake manifold (1997 models) or on
the firewall . It will be a cylindrical looking thing with hoses and electrical plug
connection to it.

(Leak detection pump is under the battery holder. )

The canister is a charcoal activated unit that absorbs fuel vapours during
operation and releases them into the intake manifold via the purge control.

When the engine is up to temp, the purge control solenoid allows the
purge control diaphragm valve (in the charcoal canister) to be opened
and vapours are drawn through the diaphragm valve by intake vacumn.

The PCM controls the purge control solenoid. During normal operation
the PCM cycles the purge control valve 5-10 times per second.

(Some models also have a leak detection monitor system which will have
its own set of codes. )

So if the fuse for the purge solenoid is blowing, it's got a overload fault
of some kind and needs to be checked out, and possibly replaced.
Solenoids normally as a rule don't short out, but can stick in operation,
causing high amperage on the +12v supply to be drawn above the
rating of the fuse and that can cause it to melt.
 

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The Haynes manual for the Durango/Dakota has the electrical flow charts
and wiring diagrams for all the circuits and sensors used.
Very useful investment, if you can read wiring diagram symbols
and understand wiring colour codes provided in it.

For the EVAP system: Leak detection pump is supplied (fused) (pin2) from the ASD
(automatic shutdown relay). The leak detection pump pump solenoid control Pin 3 (gnd)
is supplied by the PCM control.
The leak detection pump switch sensor supplies a signal to the PCM on pin 4.

The purge solenoid is supplied by 12v via a contact from the ASD relay
(10amp fuse in PDC) through joint connector #1 (PDC) to pin 2 on
the purge solenoid. Looks like a DB/WHT wire (Dk Blu/white) according
to my wiring colour code interpretation.

The gnd side to the purge solenoid is sourced by the PCM (pin 1 on the solenoid)
PK/BK (pink/black).
 

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Discussion Starter · #4 ·
Well i looked through haynes manual and found that the seat belt sensor also goes through that fuse. I unplugged it and fuse hasn't blown for about a week now.
 

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voltage for purge valve solenoid?

A good friend was helping me with my P0455 problem and measured 4 volts at the purge valve solenoid. Off of the pickup and on his work bench, it took 12 volts to make the solenoid operate.

Only 4 volts would probably explain the error code, but the question is ...
why only 4 volts and how is that possible?

2000 Dakota, V-6.
 

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4 volts at the valve when the valve is being actuated? or all the time. that code is for a large leak. could be a number of things. normally cracked hoses.
 

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After driving to his house and disconnecting the wires to the solenoid, the engine was started and that's when the 4 volt measurement was observed.

I've checked the hoses and all are pliable and securely connected. I've owned this truck less than 6 weeks and noticed the previous owner installed a new gas cap. So I suspect he knew there was a problem but disconnected the negative battery terminal to make the "check engine" light temporarily go away.

I've not checked the hose connection to the gas tank, but will do that.
 

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The 4 volts is used as a reference for the computer to verify a closed circuit (emissions components in place / solenoid electromagnetic coil not shorted) if it cannot it will trigger code P0443. The computer will trigger 12 volts to activate the solenoid.

P0455 is definitely indicative of a large leak, as Niebs stated already. Check all hoses, lines and connections to start with. If no problem found check for excessive moisture in the lines if you're in a cold climate area where moisture can freeze up your emissions components. Check PCV valve for free movement and clean/no moisture as this can contribute to excessive moisture and cause the solenoid to stick causing the code and, if the solenoid worn/internally shorting, cause the fuse to blow.
 

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still looking

Northeastern Oklahoma, temps in the 50's & 60's till recently so I don't believe it's a temperature/moisture related problem.

I double and triple checked every hose dealing with the canister, solenoid and purge pump (?), topside and underneath and found that all of the hoses were very pliable and had no cracks or slits. As far as the gas tank, I have no idea how to access the hoses/lines for it.

I tried to remove the PCV valve ... must be a trick to that as I could not get it out to see if it would rattle.

My electronics guru was not available to help troubleshoot that aspect of the problem, if indeed that is the solution.
 

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I would definitely verify the hose from fuel tank to evap canister and, if the gas cap has been replaced with an aftermarket I would question that as well for the triggered code. A cheap aftermarket cap rarely works on these evap systems. The last thing would be a faulty evap solenoid that has stuck in the open position. As the "piston" in these valves operates in a nylon cylinder surrounded by the magnet coil made of wire. If it has worn through it can short against the wire cause the blown fuse issue as well as cause the solenoid to stick open triggering the leak code.

But, before throwing parts at any problem, always take the time to eliminate all the cheap/easy issues that 99% of the time are the real cause.
 

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I would definitely verify the hose from fuel tank to evap canister and, if the gas cap has been replaced with an aftermarket I would question that as well for the triggered code. A cheap aftermarket cap rarely works on these evap systems. The last thing would be a faulty evap solenoid that has stuck in the open position. As the "piston" in these valves operates in a nylon cylinder surrounded by the magnet coil made of wire. If it has worn through it can short against the wire cause the blown fuse issue as well as cause the solenoid to stick open triggering the leak code.

But, before throwing parts at any problem, always take the time to eliminate all the cheap/easy issues that 99% of the time are the real cause.
Hmmm - you must be psychic!! Whoever owned the truck before me did indeed install an aftermarket gas cap, one that has a single click when properly closed. I found the original gas cap in the bed of the truck and by blowing & sucking, it seems to be okay. The 2" diameter seal is pliable with nothing to indicate it won't work properly. I suspect the previous owner thought a bad gas cap might be the problem and swapped it out.

I checked the small (3/16" ?) line from the tank to the evap canister and found nothing wrong with it. A person is limited in that the entire length of the line is not accessible.

A second evap solenoid (that's know to be good) was tried with no success. I examined fuse #11, 10 amp "purge" fuse. It was okay.

I'm puzzled but not giving up.
 

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Definitely not psychic - you posted a remark about a new cap there somewhere! The only other thing I can think of is if the canister itself is leaking. Mark and pull all the vacuum lines and cap the canister ports and gently pressurize it to check for leaks. If that's not it then it will have to go in for a full system leak test at the dealer. Definitely keep us up to date on what you find either way!
 

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Strange but possibly the answer

I was recently about to run an errand but the Dakota wouldn't even crank over. Absolutely nothing happened when the key was turned. I noticed green corrosion around the positive battery terminal even though I had cleaned it thoroughly when I first bought the truck, not all that long a go. Under close examination, I realized the + battery cable could be lifted off of it's battery post! The previous owner had let it go so long that enough material from the clamp was corroded away that insufficient contact was being made even though the bolt/nut was as tight as it would go. I added a home made shim (from a shell casing) and that fixed that problem.

Since the battery cable was disconnected, the check engine light was turned off and no code is displayed. Over 100 miles later, still no check engine light! Is it possible the P0455 code was being displayed because of the extremely poor connection of the + battery cable?

Perhaps power to the Purge Pump was sketchy.
 

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I suppose its possible. the light should come back on by now if the purge circuit was faulty. loose/ corroded battery connections can do some wacky stuff. always check and make sure they are clean and tight.
 
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