Hello, I could sure use some info on this one.

My '96 F150 XLT 5.0 (manual trans) has 110,000 miles. It runs perfect and I do my own work on it. Since I bought it three years ago, the check engine light has been an issue for me (even though it runs great). I got it smoged the past two times by clearing the codes. Today it did not pass, even though the check engine light was off.

I was told the OBD was not receiving signals from three systems. Previously, while the check engine was on, I took it to AutoZone, and they said they were not getting a signal from the OBD either.

I would greatly appreciate some leads so I can get this fixed. I have no $$$ for a dealership solution.

Thanks!!!

 

Need the fault codes if any.... Can't guess.

That said, if you had recently reset the PCM (CEL), it takes a certain amount of time for the PCM to re-run all its readiness monitors. In the meantime, you will have an P1000 code. Since most emisssions tests now rely solely on the OBD-II system instead of a treadmill/sniffer test, the PCM must have all (or almost) of its monitors complete and passed. Sounds like you reset the PCM just before you went to the testing station. If so, you will need to drive it awhile to allow the needed monitors to run. This can be frustrating as is sometimes takes days, even weeks, for everything to run depending on your driving conditions and style.

Steve

 

Thanks. That's the issue though, no codes. BEFORE I reset the computer, AutoZone still could not read the OBD. That said, I searched and found an old thread about a fuse. Sure enough, the fuse was blown. I am heading to AZ this morning to see if they can now read the OBD.

Thanks again

 

OK, AutoZone checked it this morning. The issue seems to be OBD P0443 , which indicates a malfunction in the purge control valve of the evaporative emission system. AutoZone had no idea how to fix this and showed no purge valve in their parts list.

Any ideas would be greatly appreciated!!!

 

A few portions from the factory diagnostic:

The CANP valve is located in the vacuum line between the throttle body/intake and the charcoal canister. On your truck, IIRC, it's on top of the engine near cylinder 1.

Steve

 

Thanks a ton Steve, I will check this out tomorrow. It is started it make me think though, there have been a few occasions when I start the truck up and the electrical goes crazy. The turn signals don't work, all the dumby indicators are on (i.e., ABS, check engine, etc.). I turn off the truck, wait a second, turn it back on and everything is fine... I hope I can find out where the issue resides tomorrow.

Thanks again!

 

OK, I took a look around, but it is still rather confusing. One immediate find was a disintegrated vacuum line coming off the throttle body. It was coming from a nipple on the TB that connected to a lone plastic tube that connected to a black box near the fire wall. I think this "black box" is connected to the carbon canister... Is the carbon canister located below the battery (and off set towards the motor)???

Could this line being torn cause the check engine light? I disconnected the battery to reset the PCM. I hope this works. How long should I wait until I try to have it smoged again?

Thanks!!!