So... p1451. Vent solenoid. I pulled the part and put 12v to it. Opens/closes just fine. Checked resistance on part, 55ohms like it should. Pulled vent canister, no apparent leaks or blockages. I traced wires back to cab. Cannot locate anybroken wiring. I looked up the pinpoint test on this dct and all thats left to test out is the pcm itself. Before I buy the obd2 scanner with all modes I wondering if I am missing something.
I did find a broken ground wire in my searching. Frame to body. My thoughts on a bad ground are that that would cause more than one monitor to register one fault code.

 

Welcome to FTE

Good troubleshooting effort so far. Did this problem come about suddenly after some event?

Since doing the suspect part testing & finding the open ground & waiting to come by a scan tool that can monitor & display live PID 's, I'd maybe try resetting the computer/wiping the trouble code & see if it returns.

This is a link to info about the code, but sounds like you have as good, or better, https://www.obd-codes.com/p1451-ford

Since you seem to like doing your own trouble shooting & wrench turning, if you have, or can come by the inexpensive ELM scan tool, running FORScan diagnostic software on the viewing device of your choice, as discussed here, https://www.ford-trucks.com/forums/1...-scantool.html, have it scan for more code clues & set it's dashboard display to have a look at the evap system live PID's, to see if it can narrow down the trouble shoot & suggest where best to look next.
Post All code Numbers, as they can help focus a trouble shoot.
EDIT: Post up all of the vehicle info, year, engine, body, mileage, recent repairs, ect.
Some thoughts for consideration, let us know what you find.

 

Hey bro, thx for the response. The truck is the Mazda B4000 4.0l 4x4 se. 1999. 265,000.
I have had it since 236,000. New alternator and fuel pump.
While trying to pass a new york state inspection I failed. The CEL light bulb was shot. I didn't even know there was fault code. The one thing that I have not done is reset the onboard after finding the broken ground. I was hoping the monitor would cycle and the CEL would go away on its own. Because I haven't purchased a scanner yet the only way for me to reset is by removing the positive battery terminal. I'm not sure if this is the best way. I guess I should, the truck isnt legal right now and though I have my little heart set on buying a scan tool w/bi-direction I really do need to solve this riddle.

 

Ok, good feedback on the vehicle info & your location. With the mileage, & seeing as how your in the rust belt, grounds & electrical connecters pins/sockets corrosion probably belong on the suspect list too. Maybe try a wiggle/thump test on components & connections, if resetting the computer & after fixing the faulty ground doesn't clear things up.

Shut the engine down, make sure All electrical loads are turned off, Then disconnect the B- battery cable, not the B+, then open a door, or push the cigar lighter in to apply a electrical load to discharge the KAM memory. Turn off All electrical loads Before reconnecting the B- cable.

Then to eliminate possible drive ability problems, have the vehicle fully cooled down & perform the cold & warm idle strategy relearn routine here, https://www.ford-trucks.com/forums/s...9&postcount=12 & let us know how it goes.

 

On the CEL, it'll light up at KOEO for a self test, so that way we know if the lamp is ok.

If you don't have the Owner Manual, go to this forums index page & click on the "Tech Info" thread atop the page, when it opens, scroll down to the "Misc" section to find a no cost Owner Manual down load link for your year truck. That way you'll have info on the specified scheduled maintenance & replacement maintenance parts. Ford/Motorcraft parts are of good quality & recommended.

 

CEL bulb is good. I am about to do the reset and warm/cold relearn. I will post results....

 

Just remember that the relearn could take quite awhile, even 150-200 miles.

 

All six monitors yea. We were just talking about the at idle relearn. If I remember correctly that is the first check performed by pcm.

 

Ok, quick update. I performed the reset and warmcold idle strategy exactly as you outlined.
I took the truck 10 miles around the block. So far, so good.
What is promising here is that after the shop reset CEL came back almost immediately. This will be the first reset after fixing a broken ground strap.
If I can get 80 miles in by 4pm monday I will drive directly to the shop. If I leave with a sticker we can close this thread. Thank you for your help and I will post another update soon.

 

Ok good feedback, let us know how it goes.

 

If your going to take it in Mon for a retest, have a read here https://www.ford-trucks.com/forums/2...ml#post1469870 on the Ford IM drive cycle to reset the emissions monitors & scroll down to note the info on the evap system drive cycle.
More thoughts for consideration, will be interesting to hear how it goes.

 

Hey. I recieved the Autel AL519 in the mail yesterday. When I tried to access mode $08 it claims 'mode not supported'. I guess the truck is too old or I need to update the scan tool. Anywho the MIL came back. I tested the resistance on the vent solenoid wiring and it is over 25ohms. So, that indicates an open curcuit I believe.
Crappy month. The pinion bearings in my truck are dust. I opened the housing. The gears are still good. Any idea if a rear end from an '06 ranger will fit my '99? Right now I don't care about ratio and gear size. I need to get to work. I am reading all over that they are compatible. I got a line on a 2006 ext cab ranger, runs and drives, with no title for $200.

 

Ok MIL is back on, so what code Number/s are stored now?
How did the scan tool read the IM & drive cycle readiness?

 

Scan tool reported one dtc. P1451. This tool has I/M readiness. Before I reset the memory again. It was listing the evap monitor readiness as INC. Also the CAT monitor waa INC. Everything else ok. This is getting highly technical now. I can't really follow the pinpoint test because the first test is command the canv on and use a test lamp to test the curcuit.
I am sitting at the truck right now. I just tested the canv again and it reads 58 ohms. The pinpoint test says check three resistances. 1 - to + on the solenoid. 2 b+ harness to - solenoid. 3 vpwr (- harness) to - solenoid. Am I interpreting these steps correctly?

edit: ok, i am overthinking this. B+ is vpwr.

edit: ok, I ran all the tests. The last test is: test v across + canv harness to - ground. If voltage is lower than 1 v replace pcm. If not repair short to pwr. My reading was .12 v off the ground strap I repaired and .04 @ B-.
Now I'm fffed. I read its over $200 to reflash a new pcm on a truck with anti-theft.

 

Ok the 1451 code is back. SO, lets think about this some more. I'd consider performing some more wiring run inspections & wiggle tests, before throwing a new ECM at it.

With the purge solenoid electrical connector Disconnected, back probe the wire at the computer firewall connector & see if voltage is there from the computer. If it is, then you have a wiring run high resistance, or nearly open circuit conductor problem, between the computer firewall connector & the disconnected purge solenoid connector.

If still no voltage at the computer connector when back probed, it could be a wiring run short to ground, that's loading the circuit down, so disconnect the Wire at the computer electrical connector & back probe the Firewall computer contact socket of the wire you just removed, for voltage. If you still don't have voltage, the computer has a problem. If you Now have voltage, the computer is ok & you have a wiring run with a short to ground that you missed on your visual inspection or wiggle test, that's loading the circuit down.

So, check the disconnected wire to ground, if you have a reading, set your multi-meter to "Beep" again & do another wiring run wiggle test & when it stops beeping, you'll be at, or close to the short to ground spot.
Then look for a rub spot on the wiring insulation where it contacts something that moves, vibrates, is hot, or maybe someone has incorrectly rerouted the wiring.

If the problem is thought to be a open circuit in the wiring run, you could short the solenoid end to ground, probe the disconnected computer end wire with the multimeter lead, the other meter lead to ground & try another wiring run wiggle/push/pull test to see if you can cause it to make contact at the broken strands point & cause the meter to beep. Then look for signs of wire damage close to that spot. Look for insulation pinch/mash signs, or insulation swelling, where the wire strands are broken under the insulation. Good spots to inspect are where the wiring run is stretched as it rounds a bend, or is routed over something that moves, or vibrates, like the transmission, or engine, pedals, throttle connections, ect.

If you come to find the ECM is faulty, check out FORScan & running the inexpensive ELM scan tool, as the latest versions of FORScan can now do a lot with PATS programming.

A bunch more thoughts for consideration, let us know how it goes.