Flex Fuel P0176 DTC

[Outcast]

I have a '00 3.0 ranger w/flex fuel option. I recently thru a check engine light code of P0176, Which is supposed to be a fuel composition sensor circuit malfunction. called a flex fuel circuit malfunction by some. My truck thru this code just after I added a bottle of dry gas! I have a hard time beleiving there is enough alcohol in there to cause any kind of malfunction in the flex fuel system. Anyone else have this problem or just ME.
Could it be coincidence? I haven't run the whole tank of gas out and tried to clear the code yet. Just wondering if I should warm up my check book!
Thanks for your time

[rwenzing]

P0176 - Flexible Fuel (FF) Sensor Circuit Malfunction
"The FF sensor input signal to PCM is continuously monitored. The test fails when the signal falls out of a maximum or minimum calibrated range."

This sometimes requires replacement of the FF sensor which is part of a larger assembly. It is very expensive ($400?). Before throwing any parts at it, I would run some more fuel through it and reset the PCM by disconnecting the negative battery cable for a minute or two.

Here is the complete list of possible causes from Ford:

-Open or short in FF sensor VPWR circuit
-Open in battery ground to FF sensor circuit
-Open in FF sensor signal circuit
-Short to ground in FF sensor signal circuit
-Fuel contamination
-Short to VPWR in FF sensor battery ground circuit
-Short to VPWR in FF sensor signal circuit
-Fuel separation
-Damaged FF sensor
-Damaged PCM

[GodAmRanger]

Bringing back and older thread..

Last night, in the crappy weather, I happen to hit a few puddles which triggered 2 things:

ABS Light
CEL

The code was the P0176, same as the original poster.. I sort of assume that the puddle may have got something wet, however, I wanted to see what, if anything in that list, could have gotten wet.. Any ideas?? I'm far from home, and have minimal toolset with me to take stuff apart, and at $400, I'm not a huge fan of replacing, if I can check other things first.. Oh yeah, I don't have a manual, so a general area to look would be good too..

TIA


JT

[rwenzing]

I would try cheap and easy first. Look under the truck near the transfer case directly below the driver seat and you will find a 40-pin connector. It doesn't like water and has a habit of shorting all sorts of things together that relate to the rear half of the truck. Use a 10mm socket or wrench to open up the connector and you may find water/dirt/corrosion inside. Clean and dry with electrical contact cleaner and reassemble. If you can find dielectric grease (about $7/tube at auto parts, electrical supply house or Ford dealer), pack the pin area full of it before reassembly - it helps keep the water out. Good luck.

[GodAmRanger]

Sweet.. Thanks for the response.. I wish I could have read this sooner, since they block this site at work.. I'll give it a shot..

Is there some sort of gasket that supposed to keep contaminants out?? Would wrapping it in duct tape help keep the crap out??

Thanks again!!


JT

[rwenzing]

Is there some sort of gasket that supposed to keep contaminants out?? Would wrapping it in duct tape help keep the crap out??

The connector has rubber seals top and bottom but they are not 100% effective. The dilectric grease is the way to keep the water from making electrical contact with the pins.

[GodAmRanger]

Okay, so as always, you're 150% right... Got the connector off today, and all sorts of water and sand came out.. Cleaned it off and seemed like the corrosion was pretty bad, but got the grease in there and threw it back together, reset the PCM; however..

Friday morning, I started the truck, CEL was not lit.. I was psyched.. Well, about 8 that night, I'm pulling out of my buddy's street and the truck just dies.. I throw it in Neutral, starts, but it seems like it's only firing on MAYBE 3 cylinders.. I floor it to keep it running, get it back to the place I was staying, turned it off, then started it again.. It was misfiring, but not as bad as it was before.. I mean, it was still missing, and it died a few more times. I parked it for all of Saturday, and then went out, went over all of the connects (plugs, wires, coil pack, PCM harness, O2 sensors, the whole bit).. Truck starts, and has a methodic miss.. Well, it ran, and didn't die until this morning.. A few guys I work with work at the motorpool, so they ran the codes.. One of them, the Fuel compensation Circuit Malfunction was back, along with Ignition _____ Malfunction. They didn't get me the codes, but once we cleaned the FFM connection, it ran better, and the codes went away until I drove home..

Now the CEL is on, but I have a feeling it's for the Ignition ____ Malfunction.. It used more fuel than normal, but the power feels 99% there..


Any ideas besides swapping the Coil pack?? There was no random misfire codes, or anything like that, so the guy I work with thinks the coil pack may be on it's way out..

BTW, the plugs and wires are all brand new, Iridium plugs and Motorcraft wires. I'm going to try pulling wires individually to see if I can isolate the cylinder that's bad, hoping maybe a plug is just fouled, or something..



JT

[GodAmRanger]

Back to this crap again.. I had the codes ran again, since the light went out and came back.. Sure enough, same code.. I'm starting to think that I'm going to have to either replace the pins in the connector or splice in a new connector.. Has anyone heard of doing either of these?? I know rwenzig mentioned taking the connector apart and then replacing the pins, but I figure it'd be easier to splice in a good known harness..

Also, does anyone know if Ford sells just that specific connector?? I tried talking to the parts guy and he didn't know what I was talking about..



JT

[Rockledge]

Sounds like the sensor itself might be bad.

[GodAmRanger]

I hope not, since it does cost a ton.. I'm going to see if I can get some pictures of the connector to see if you guys think the slots are too corroded.. A few of them looked bad, but I can't be certain which pins do what..

The good news is, the ABS light hasn't come on since.. It seems like I've had a few other electrical system gremlins, since the other day, I started the truck, and the BRAKE light stayed on (brakes felt fine) and my CD player wouldn't work.. I turned the truck off, started it up, and everything was fine again...



JT

[rwenzing]

I agree that the sensor could be bad. If you want to give the wiring one more try, the color codes to the Fuel Composition Sensor are

light blue/orange - 12volt power
black - ground
dark green/light green - sensor out to PCM

If you want to buy a new connector, check at the Ford dealer. Motorcraft offers repair connector kits for many areas on your truck. Be prepared for a big price tag. I don't know how much for a 40-pin but I bought a 6-pin once for about $40.

A junkyard connector could be a much cheaper alternative. Just be sure to check the condition inside before you buy. And you'll probably want to stick with a 99~00 3.0 Flex to get an exact match on color codes.

You might also be able to run individual repair wires outside of the the 40-pin if you only have a few bad ones.

[GodAmRanger]

Sweet, thanks for the wiring colors.. That's crazy that it costs that much for a harness repair kit..


Thanks a ton for all the help!!! It finally stopped raining, so I think I'm going to try and do some mild rewiring today.. I'll let you guys know how it works out..




JT

[Rockledge]

Good luck with the troubleshooting.

If you ultimately determine that the sensor itself has failed, and you are not intimidated by a little electronics, then you might try out this prototype Ford FFV sensor "emulator".

[GodAmRanger]

That's awesome!! I'll assume you can get all of the resistors, and even the white thing (circuit block maybe?) at Radio Shack or something like that?? If it is the sensor, I may indeed go that route..

Thanks!!


JT

[Rockledge]

According to the guy that designed it, yes you can get the materials at most electronics shops.

Inasmuch as there has not yet been any feedback regarding the unit, it is still to be determined just how well the FFV emulator actually works (if at all). That's why I referred to it as a prototype.

[GodAmRanger]

Well, I figure, for the price of the goods, even it it partially worked, it's a small victory.. I'm no electrical engineer, but definitely know a little bit about electronics principles..

Ironically, enough, the CEL went out last night and has yet to resurface..

Aggravated?? A bit, but I'd rather not see the light, than be experiencing power train electronics malfunctions.. I also noticed, that when the CEL was lit, the truck suffered a bit worse with regards to gas mileage.. Then last night, I was seeing almost 23-24mpg, something I haven't seen since i owned a civic..



JT

[GodAmRanger]

So it's been a week, and the light is still off.. Gas mileage has got a little better, but other than a 4wd truck with 122xxx miles, and gas at $4 a gallon now, it'd be nice to own a motorcycle..

I found a harness that was in good shape, but I'm going to wait to splice it in, just in case it was a hiccup.. The harness was cheap, however I think I may still see if I can build one of these emulators and give it a shot.. What's the worst that can happen??



JT

[300zxranger]

any update on your truck, iam having similar problems