Hi all,

1997 Ranger 4.0l OHV. 195k miles. Ever since we've had this truck, intermittently we'd get CEL and codes related to the Evap system. I've repaired hoses, replaced the purge sensor and the purge valve before, put on new fuel cap (also replaced filler neck, but that was due to a leak in the filler neck). Anyway, the codes went away for a long while, or they would need to be cleared once in a great while. Now, I get a very consistent P1443. From reading other threads, I believe this means the purge sensor is detecting no or low flow from the purge valve, with engine running.

1. I tried the 9V battery test (that RonD described in another thread) on the solenoid valve and it does operate. I can hear it click, and checked air flow by blowing into it: valve is definitely closed on 0 V and open on 9V.
2. I checked the key on voltage at the 2-pin female connector for this valve and it shows 12v engine off and about 14 engine running.
3. With key on, it seems as if when I insert the connector, I should hear a click, but I don't. Confirmed no airflow with key on, engine running or not.
4. So, I guess I suspect the connectors are not mating correctly. I sprayed some contact cleaner in each, but still no luck.

Am I diagnosing this correctly, do you think?
Is there a replacement connector (the female half on the wiring harness) that I can get without changing out the whole harness (yikes)?
Edit: I found one online for $25 at O-Reillys
Should I just try another purge valve since they aren't expensive?
Edit: Well, I found one at O-Reillys for $62 (Standard Ignition) or $110 (Motorcraft), so I guess they aren't exactly cheap.

Thanks much,
Dave

 

Solenoids, in this case vent/purge valve should get 12v one one wire with key on, the other wire runs to the computer, the computer will Pulse a ground to open the valve a little or a lot based on its software
So no, solenoid shouldn't "click" when plugged in, key on or off, the EVAP system is not used full time, once you are driving the computer should apply vacuum via the valve and then wait and see what the EVAP "pressure sensor" does

P1443 Evaporative Emission System Control Valve (low/no flow)
Its applying vacuum by no or low flow detected by "pressure sensor"

This is not a Circuit Code, so on the face of it the wiring and electrical components are OK, but computer is not detecting "flow" in the hoses when there should be
This is a tough code to find the cause, because it can be a computer issue, internal circuit issue

 

Thanks, Ron -- makes sense to me. Well, at least I know the valve will indeed open up. So, I think maybe I'll head down the road of seeing if there are any leaks detectable somewhere (I read your description of applying positive pressure through the tank filler opening and listening for leaks). Another idea would be to just spend the bucks on a new purge sensor to see if that changes anything.

I'll come back and report results.
Dave

 

EVAP systems are one of the worst to diagnose

On the surface it seems like it should be easy, lol
Apply vacuum to a sealed tank(gas tank), if pressure holds then no leaks
Then switch to slight vacuum to suck out any fumes from the gasoline sloshing around in the tank while driving, and burn the fumes in the engine
Easy peasy
NOT

 

Reporting back: I decided to just replace the purge flow sensor. After several trips driving around town today, no CEL so far....

O'Reilly's guy said it comes with a lifetime warranty -- I don't know if he means mine or the truck's, but if the code throws again I'll take it back!

Thanks again,
Dave