2003 explorer sport trac p0443 help

kevin phillips · April 3, 2009

I have a sport track giving me a fit.Checked out vehicle ran evap test found vapor management valve not working.Checked power and ground to valve ok with valve disconnected.Vehicle has no ground on vapor management valve with circuit loaded.disconnected pcm and valve and load tested both the power and ground circuits check ok.load tested powers and grounds to pcm check ok.Replaced pcm,still same issue loss of ground when loaded.Any ideas or suggestions? on where to go from here. The pcm is new and the wiring has been checked and double checked on those circuits above.Could this be a issue on another system causing the ground to drop from pcm?I'm lost from here.thanks for any suggestions

Mekanik · April 4, 2009

Have you done the evap test with IDS?

Can you manipulate the canister purge valve and the vapor managment valve with IDS while monitoring the FTP voltage?

I believe the PCM provides the ground for the VMV, so you would need to activate the VMV with IDS to test the ground circut.

I have replaced many fuel caps and canister purge valves for p0443 and p0455. I have also had many others that I test and do not find a leak.

Jim Warman · April 4, 2009

Kevin.... we desparately need to be on the same page here.... Let's be brutally honest - this car has a new PCM and the concern is still here.... Something has ben missed... Sorry, bro...

What are you using to load test the wiring? I understand this is a hard fault? (Read that as OnDemand code). The PID for the VMV should have a pound sign - # - meaning we can control it... meaning we can place our hand on it and feel it click when we toggle it's state?

Every pinpoint test ends in replacing a module.... it gets there because the PPTs that Ford describes are shit

Mekanik · April 4, 2009

I'm sorry. I was thinking P0442 which is a small leak detected. I looked at the definition of P0443:

The PCM monitors the state of the EVAP canister purge valve circuit output driver. The test fails when the signal moves outside the minimum or maximum limit for the commanded state.

Are you looking at the canister purge or the vapor managment valve? The canister purge is under the vehicle toward the rear, and the VMV is either under the hood ou tucked in a fenderwell.

Like Jim said, if you are trying to manipulate an output device and there is a -!- instead of a -#- it is because for whatever reason the conditions are not right for IDS to control the actuator. For example if the engine is running and the transmission is not in park or the wheels are spinning a little bit in neutral, the PCM will not let you control the actuator.

kevin phillips · April 6, 2009

I have tried to operate both the evap vapor management valve and the canister purge valve with the ids. The canister purge valve at the rear of vehicle works fine and is operational.The vapor management valve at the front of the vehicle under battery tray however is not working when commanded with ids.There is a # symbol and the system allows me to change the percentage up to 100% .Fuel tank pressure does not change during evap ids test so it fails the test.I used a fog light bulb to test the wiring.I removed the evap hose to the fuel tank from vmv and commanded on the vmv and no vacuum was present there thus no change in ftp.Thanks

Mekanik · April 9, 2009

Did you figure this thing out?

Is it a KOEO DTC or continious?

I don't understand how you are having troubles with the VMV when the DTC is related to the canister vent soliniod.

kevin phillips · April 10, 2009

Customer came and got vehicle to let someone else try it.I have no idea where it was at but the vmv would not work.The canister purge selonoid worked when tested.I may have been going down the wrong path but the the book lists a canister purge valve and a canister purge selonoid.The valve that connects to manifold vacuum and the evap system system up front was the one inop electrically.The vehicle was involved in a wreck a few months back and i believe they had some explorer harnesses on a sport track which were diffront and causing a issue due to diffront wiring between the two.Thanks for the help guys

DamageINC · April 11, 2009

IF you're confident that you had a good power source, you could always jump the ground side of the VMV (disconnect the pin from the PCM and jump that end) directly to the battery with source voltage applied just be sure that the VMV actually works.

Although now I see that the vehicle's no longer in your hands, which kinda sucks.

If indeed the whole physical (wiring/component) circuit is in good shape with a solid 12v source reaching the VMV and a good clean ground ckt to the PCM, and it has a NEW GOOD PCM as well, then the only thing that I can see causing the PCM to not ground the VMV when commanded is if the PCM itself isn't recieving suffecient power. Low voltage/current supply to modules can cause some drivers/transistors to not function properly without causing ANY OTHER problems at all.

The ground ckt can also be checked by tapping your DVOM into the ground circuit WHILE the VMV is commanded open (grounded) and seeing if you indeed are getting a path to ground through the PCM. Also, check for any voltage on the ground ckt right before the PCM just to be sure there's no extra resistance on the ground side.

Dave