Hi all...my truck ('97 F150 4.2L) has been throwing a CEL P0443 code (EVAP system). Truck runs fine, idles fine, no problems. The problem is it's due for it's yearly inspection (Texas state law) and it won't pass with an active CEL. I replaced the purge solenoid valve and it is still happening. I finally took it to the dealer for their diagnosis. They told me the ECU needs to be replaced, but it's discontinued thru Ford.

I found remanufactured ones (Rockauto.com and NAPA), but still have a question. There is a calibration sticker on my truck that reads "7-43E". There is also an ECU code sticker that reads "EEA2". Rockauto and NAPA both use the 7-43E number for the correct flash. Is that all I need to match so I can just swap one for the other? Would any other programming be needed with the replacement ECU? (truck is 100% stock) Is the VIN info stored in the ECU?

Thanks in advance for the help.

 

Did you replace the vent solenoid valve on the canister (under the rear of the truck) or the purge valve under the hood?

Did you verify wiring harness integrity to be certain the solenoid has proper electrical connections?

Steve

 

I replaced the purge valve under the hood. (Driver's side firewall)

 

Wow this is interesting... I wonder why Ford discontinued them?! I think that is bad, because if your truck dies because the ECU, you wouldn't be able to get a genuine Ford one.

It's like Ford forcing you to get a new truck because of a computer.

 

It's an 11 year old vehicle. Manufacturers are NOT obligated to supply spare parts forever, much less that long. That's where the aftermarket comes to play.


Did you verify wiring harness integrity to be certain the solenoid has proper electrical connections?

 

I did follow the Ford diagnostics and verified the purge valve had the correct resistance and voltage. Can you explain further?

 

I think what people here are trying to say is this - it's VERY rare for an ECU to go bad without totally disabling the truck. The problem is a lot more likely to be in another component, sensor, or in the vehicle wiring.

ECU replacement requires VIN programming, which Ford may charge you an arm and a leg for if you don't buy the ECU from them.

 

I'm open to suggestions. Dealer told me EVAP system checked out fine, but the ECU is still showing an error.

 

Sounds like you need to be looking to the rear of the truck.

My gf's focus has something loose on her evap system and it involves removing the gas tank to tighten what ever is loose. we get a gas smell if we fill it up.

 

No, he's looking in the correct area.

I'd suggest performing resistance chacks on the harness of the CANP valve wiring to be certain it's okay, to and from the PCM and to the supply voltage. If it is, then I'd agree that the PCM has likely failed (faulty ouptut driver, most likely). Such a failure would be limited to a single function of the PCM .

Steve

 

Thanks for the info Steve, I appreciate it. Is the testing you mentioned documented anywhere?