Hello Everyone!

I have a '97 F-150 XLT, 4.2L with standard trans. I have been troubleshooting a P0443 DTC on my truck and have hit a road block that maybe someone can help with or at least point me in the right direction.

Here is what I have done so far:

1. Replaced selenoid at firewall - still pops code!
2. Key on voltage check at plug - 11.98 volts - within limits!
3. Ohm checked new selenoid - 35 Ohms- within limits!
4. Key off voltage check - 0.270 volts - SHOULD BE 0??????

That is where I am stumped - there should be no voltage with key off. My question is this - is that quarter volt enough to trigger the DTC? If so, can someone please tell my next step as I am completely stumped on this?

Any suggestions would be greatly appreciated! Thank you in advance!!!!

 

This might help:

https://www.obd-codes.com/p0443

I'd start looking at wiring issues - loose, corroded, broken, etc.

 

Thanks for that link. I did check all the wires back to the ECM, everything looks good. I am starting to think that the ECM is going bad and will probably need to be replaced.
God I hate troubleshooting electrical!!!!

 

Sorry y'all, I meant to follow up on this a couple of weeks ago.

It turns out the ECM was indeed bad. It had a bad ground circuit that failed to trigger the solenoid valve. My first clue should have been the voltage reading with the key off. I replaced the ECM and it is now error free. Thanks for the help. Hoping for another 280,000 miles out of this old girl!!!

 

Good to hear with the 280K.

I haven't been driving my truck much... only because eh... haven't felt like it. For the past 3 years its been a sincere garage queen.