The pesky CEL is back. Has anyone had a similar situation?

[Sdude2008]

Hello. Had a CEL with code P0176 a couple years ago 2020. Truck has a fuel sensor replicator. Around smog check time the code went off and the truck passed. 2021 the cel came back P0176. I cleaned up the connection with no change. Then again the cel was gone. Took it to the smog check and they said it was too soon and the sensors needed to reset. Retest time has come and gone and now the light is back as registration time approaches. I ordered a new replicator and it didn't help.
My question is has anyone determined some other resolution to the P0176 code other than the senor/replicator replacement. I've checked as much of the wire as I can and find no breaks. I've read something about a problem within the ecu? Any suggestions on what else to do besides the $$$$$ og part are appreciated. Meanwhile I'll keep reading.
Thanks in advance and as always for the great help.

 

[Sdude2008]

I've been doing more reading and have no new ideas. I guess I'm just delaying the inevitable trip to have it scanned and diagnosed. It just makes me wonder how the cel can stay off for a prolonged period then reappear without anything being changed.
Anyway thanks if anyone has some alternate experience.

 

[ericbphoto]

I don't have any experience with that circuit. Someone else may chime in with better info. But, a Google search brought me to this.

 

[Sdude2008]

Thank you.

The sensor wire goes to a large plug under the floor. I'm looking up how to disconnect those plugs to clean them.

 

[Sdude2008]

Cleaned both plugs no change. Off to Ford. ugh.

 

[RonD]

You can buy a Bluetooth OBD2 reader for under $15
You use your phone or tablet as the display, APPs are free or $5

You can read and clear codes, of course, but also see LIVE DATA on the screen with while idling or driving(using hands free right?, lol), you can see what the computer is seeing from each sensor

Works with ANY vehicle 1996 and newer, Ford, GM, Audi, Honda, ect.......................any vehicle, its a Law, so good tool to have

P0176 is a fuel sensor code so would only come up on Flex Fuel models and only in some years, 1998-2000

It may be a computer issue, and because of PATS it would be hard to swap computers in 1999 and up Rangers
New computer and PATS module(above glove box) need to be "married" which requires Ford Software on a laptop
Forscan software may be able to do it, not sure, I know it can program new PATS keys
You could look on Forscan forum for more info

 

[RonD]

+1 on that plug under drivers seat there were TSBs for 2000 and 2001 Rangers

Seen here: http://www.fordrangerforum.com/electrical-tech/16083-technical-service-bulletin-2000-2001-ranger-electrical-connector.html

If you have a late 1999................

 

[Sdude2008]

Thank you!

I've seen the TSB and I've taken the seat out and pulled the carpet up to find nothing. There are the two plugs under the floor which I removed and cleaned, although they seemed very clean already. No signs of water.

I have a an older Actron scan tool but it's very limited in it's capabilities. It shows active and pending codes, MIL on/off and the status of 8 sensors. And of course lets me clear the codes and turn the MIL off. Which comes back on almost immediately. Any recommendation for the ~$15 scanner?

I'm planning to stop by the dealer today and see if they can do a proper scan. My worry is they'll tell me I have to replace a very expensive sensor when that may not be the actual cause of the cel.

Not sure I mentioned the truck runs fine I just need to pass the emission test.

Thank you again.

 

[RonD]

I used an ELM327 for many years, no complaints, and the Torque Pro APP, $5

A few years ago I got a BlueDriver, $100, it can see automatic transmission codes, has its own APP

 

[rubydist]

The interwebs suggest that fuel quality or the fuel cap can cause that cel also - is the light on/off related to any particular gas station?

 

[Sdude2008]

The interwebs suggest that fuel quality or the fuel cap can cause that cel also - is the light on/off related to any particular gas station?

Thanks. Tried both replaced cap and spread gas stations.

 

[Sdude2008]

I used an ELM327 for many years, no complaints, and the Torque Pro APP, $5

A few years ago I got a BlueDriver, $100, it can see automatic transmission codes, has its own APP

Thanks. Saw the blue driver on you tube. Looks pretty good. I appreciate the info.

 

[Sdude2008]

Thought I was onto something but again the CEL popped. Pulled off the pcm plug and it was pretty dirty so I cleaned it. Nope.

Also tried to test the dg/lg wire from the sensor to the pcm but couldnt get the black plastic cover off to find the wire. Tried pin #34 but nada. How does that cover come off? Didn't want to break it.

Ford stealer wants $179 for a diag. Not giving in yet.

Thanks

 

[Sdude2008]

Updating some more info and a couple questions.

On the sensor plug the three wires with engine off and key on should be Black - Ground, Red - 12 volts, Green - 5 volts. All check out

I got a reading of .008 on the ground wire so I added another ground. Now it reads .000 (someone told me their P0176 issue was caused by a bad ground at the plug.)

I found a PCM wiring diagram online where the poster said it was a 2000 but was the same as the 1999. It indicates the flex sensor wire (dark green/light green) is in position 34.

A continuity test on my dg/lg wire shows continuity at pin 34.

I can clear the code with my little actron obdii reader. It will stay off while the truck is running. If I shut the truck off then back on the cel pops in 30 seconds. Same with the sensor plug just unplugged. This leads me to believe it doesn't matter whether I have the og sensor, the og replicator or the new replicator connected the pcm is getting no signal or isn't reading the signal correctly.

This further leads me to believe the fault lies within the pcm itself. Looks like a programmed replacement is $167. Any opinions on this?

Any other ideas are appreciated. I'm including some pics of what I see.

Thank you.

 

[pjtoledo]

the output of the flex sensor/replicator is a digital signal that changes frequency to indicate the alcohol content.
"good" code readers can display that output, as a percentage or out of range.

I would try to get an accurate reading on that wire before swapping the PCM