P1451 EVAP Control System Canister Vent Solenoid Circuit Malfunction

[2002yanks]

i have a p1451 code (EVAP Control System Canister Vent Solenoid Circuit Malfunction). motor is a 5.0 from a 99 mountaineer(and the computer). i`m triing to figure out where the wires are supposed to go(i found them coiled up under the rug). i bought the wiring diagram from http://www.wiring-diagram.com/. but it is alittle confusing. first it says cannister vent solenoid goes to purple/white to 5 light blue/orange to 6(this is on the engine performance page). then on the power distribution page its says the the light blue/orange goes to fuse 13 under the hood. i have hoocked the light blue/orange to fuse 13 like it says but where would the purple/white wire goto? i have tried afew different ways with no luuck. i check after each attempt for continuity and volts, but haven`t had any luck. can anyone help?

 

[2002yanks]

anyone? this problem is driving me crazy.

 

[Dilbert5]

According to the schematic I have, The one wire goes to fuse 13 (as you have it ). the other wire goes thru several connectors to the PCM, pin 67. it goes thru several different connectors, but the color remains the same.

 

[2002yanks]

thats what i thought. i will have to try it(swear i tried that already). now with the key on(in the acc position) the connector should read 12 volts correct? should i splice it in near the pcm?

 

[Dilbert5]

The side that goes to fuse 13 should read 12v. The PCM provides the ground to enable the solinoid. The wire going to the pcm has several different connectors inline, so if you just want it working, I would suggest cutting the old wire, and adding a new one directly from the pcm, to the solinoid.

 

[2002yanks]

ok, i will have to go out and try that(crossing fingers). i hope this works, i have been fighting this stupid light for 6 months. need to get it inspected so i can drive it again. haven`t drove it since october. by the way this is in a 97 ranger splash

 

[2002yanks]

tried that(hooked up purple/white wire to pin 67). i now have 12 volts to the plug. i started truck 2 times light can back on. pulled codes and p0453 and p1451 came up. i thought i had the p0453 taken care of(changed the fuel filler neck and that code went away, now its back. anyone have any suggestions? this is really making me

 

[Dilbert5]

Did you clear the codes before hooking up the wire?

 

[2002yanks]

i believe i did(i aways check before i start it and there are no codes)

 

[Dilbert5]

Measure the resistance of the solinoid, and then turn the key on (engine not running). Measure pin 67, I believe that you should see 12 at the PCM (untill the pcm comands the valve on). Right now you need to confim that the circuit is indeed good. Looking at the troubleshooting guide, it ultimately ends with replacing the pcm. But of course you will need to confirm everything else is good before condeming the pcm

 

[2002yanks]

the resistance of the solinoid is 63 (brand new by the way)

on pin 67 with the key on(not running there is .18volts(had to use a pin ti fit in there). i just touched the black to a chassis ground is that ok?

 

[Dilbert5]

The .18 volts concerns me, I will try to look up a good circuit description, but offhand I was expecting 12 volt. Could you break the splice that you made, and then remeasure the voltage at the wire, you should read 12v. That will tell you that the circuit is ok. I try to look up some type of description so that we can get a better idea, before condeming the pcm.

 

[2002yanks]

do you need to drive the truck awhile to"reset" the computer to clear these codes? I have been letting it run in my garage and the light keeps coming back.

 

[Dilbert5]

I do not remember all the conditions, but the basic conditions should simulate normal driving. IE 5 or 10 min on a freeway, followed by some stop and go street driving.

I also believe disconnecting the battery (neg terminal) for awhile will also reset the code.

Just letting it idle will not reset the code.

 

[2002yanks]

ok. i will have to reassemble the truck and bring it out for a drive. disconecting the battery didn`t do it

 

[Dilbert5]

The other option is to use a scanner that has the ability to reset codes. I know some of the USB scanners can, (and most of the higher end scanners).

 

[2002yanks]

well i do delete the codes( i have an actron pocket model i believe that`s what its called). i was just wondering about the driving part. I looked at ny states dmv page and it says it(inspection stations) can tell when the battery was unplugged or if the codes were not ready. If they are not ready it says to do some driving around a certain way. I was just curious if i needed to do that to reset them.

 

[Dilbert5]

So your scanner can reset the code, and is it coming back while idling? That is not a good sign.

As far as the readiness monitors, that is the check cycle that the PCM goes thru. It is also one that the state inspectors check. The engine must go thru pre-defined cycles to set the readiness monitor, and signal that all is ok. Otherwise a person could drive up to the inspection station with a scanner, reset codes, and then pass emissions.

your state inspection book is refering to the readiness monitor. And I do not believe that there is any work around that would set these monitors.

 

[2002yanks]

yes the codes come back after the second time i start it(start it let it warm up, shut off and start again and thats when it usually comes on). now i`m also getting a p0453 code(thought i fixed it when i changed the fuel filler neck but it came back).

 

[Dilbert5]

That is not good. It sounds like the PCM is toasted, that could explain why you had initially found it disconnected. obvious that the previous owner had worked on it.

Since you have already repaired the circuit, it looks like it is time to start looking at the PCM. Disconect the battery, and remove the PCM, them remove the cover, inspect for any signs of burn damage, or overheated components. There is a good possibility that the driver for the solinoid has been shorted, and blown out.

Sorry to be the bearer of bad news.