Purge valve circuit diagram ? P0443 code issues!

[Turdle]

Thanks for looking.

Been having a p0443 code on 2003 5.4 f150

Replaced hose, nope

Replaced purge valve. Nope.
Replaced connector, seemed to for 45 miles but nope.

I now have battery tray out, I know pin 56 on PCM is the green with black 0 volt, now I am stumped as to which pin is the red with yellow stripe 12 v for purge valve. I intend to route new wire for each.

 

[Turdle]

I tested voltage, and ground looking for a possible cross to ground but found none.

Voltages are stable even with jiggle test on wiring. Still think it's the connection at plug

 

[Turdle]

@boominXplorer when I disconnected c1 connector to purge solenoid the first time I noticed heat caused discoloration to the yellow pin retainer inside harness plug.

When I changed the connector, the cel remained off. I showed my father the difference between connectors, then the cel came on during return home.

This is why I feel it is a problem n the connector itself. I used a. eBay used connector.

New connector is over 60.00 unless you have a source suggestion.

 

[boominXplorer]

I've seen those connectors have a discoloration but if it's not melted at all its probably fine. I'd check for voltage on the one pin and ohm the other out to the pcm connector.

 

[Turdle]

I've seen those connectors have a discoloration but if it's not melted at all its probably fine. I'd check for voltage on the one pin and ohm the other out to the pcm connector.

Which pins on PCM connector please?

 

[boominXplorer]

Here you go, looks like pin 56 at pcm.

 

[boominXplorer]

Red/yellow shares power with a few other sensors from the fuse box

 

[Turdle]

Red/yellow shares power with a few other sensors from the fuse box

View attachment 434126 View attachment 434129

So, either the split connection on red yellow bus, is flaky
Or the green black wire is.

Going to run new wire in place of green black, then strip loom to where this red yellow wire joins to the others.

Thanks for diagrams!

 

[boominXplorer]

Just check continuity to the egr solenoid red/yellow instead of looking for the splice. You can run a jumper from there if you need. It all goes to the same place.

 

[Turdle]

Well, dernit I replaced both wires, and code still pops up.

Connector or PCM is all that is left.

@boominXplorer , could a dirty alternator signal cause this? Tuning to a weak am station reveals some "popping" at random, brakes and shift position sensor also induce noises.

 

[donalds]

Yea it can cause it Most likely a bad diode
Bad capacitors in the PCM will also cause it

 

[Turdle]

Well, I cracked the PCM open. I can't see anything even slightly wrong.

Number 56 pin coincides with the soldered point at tip of screw. I was hoping to find a bad joint there

 

[Turdle]

Can a vacuum leak trip a p0443 code?

I find firm arguments s both ways. Some say it is purely electrical.

Well, how does pin 56 know if the solenoid operated when it is the signal path? Seems to me a pressure sensor needs to be referenced to know if the purge has occured. School me please.

 

[Josh P]

It is purely electrical. Did you check the resistance on the coil for the purge solenoid. I see that you replaced it but new parts don't mean good, it means untested. If power, ground and the solenoid is ok, the only thing left would be the pcm.

 

[Turdle]

It is purely electrical. Did you check the resistance on the coil for the purge solenoid. I see that you replaced it but new parts don't mean good, it means untested. If power, ground and the solenoid is ok, the only thing left would be the pcm.

My meter reads 3 ohms at the leads, both solenoids measure exactly 38.5 ohms with them. So, 35.8 ohms on solenoids

 

[Josh P]

My meter reads 3 ohms at the leads, both solenoids measure exactly 38.5 ohms with them. So, 35.8 ohms on solenoids

34 +/- 4 is spec so that rules that out....