Troubleshooting help needed, P0117 won't go away.

RonD · Oct 22, 2015

2000 Mercury Mountaineer 5.0L shows Motorcraft part number DY1144

Ford dealer site shows Ford number 12A648 (DY1144), for above vehicle, so same as autoparts store site

2000 Explorer 5.0l shows 12A648 (DY-681), all always thought they would be exactly the same, same Ford part number but different motorcraft part number??

oddball101 · Oct 22, 2015

Ya, I saw that too. I do actually have that part number too.

I think the needle my friend was using to test may have been providing too much resistance. When he used the needle he was getting the 2 volts with only the key on. It was when he contacted the connector piece directly with the meter, after pulling it from the sensor, that he saw the 5 volts at the gr/rd. May have had the same impact on the other side as well.

I will see if I can get better physical contacts to use and try again. At least i know that it is getting proper power to the gr/rd side.

oddball101 · Oct 23, 2015

So I have been watching it like a hawk and I ma no longer seeing fault codes or pending faults either. Like I said originally, it happened when I was driving in a spirited fashion and I haven't driven like that since. When I changed out the original sensor for the autozone one, I got the code back the same day. I then changed it out for the current one from ford (mentioned a couple posts up) and showed a pending code which later triggered and showed up with the light.

Ever since I unplugged the pcm the code has not come back up and it doesn't show as pending either. I am thinking that it may be a loose connection somewhere, or heat related given the timing of the codes. I will keep monitoring everything closely.

As of now, going through the Torque App for android, it shows my coolant temp sitting right around 192* constantly with the occasional spike to 196* and then back down. It also has a note stating, "Closed loop, using 02 sensor for fuel mix". I am hoping that is normal after the motor has heated up and shows it running as it's supposed to be.

I will be making sure all of the wire tubing and such is up to snuff along with covering up any exposed wires. I have been needing an excuse to cleane the engine bay for a while anyhow.

RonD · Oct 23, 2015

Yes, Closed Loop is what computer should be running after 5-8 minutes of warm up.
O2 sensors need to be at 600degF or higher to work, so computer can't use them until they warm up.
The engine also need to be run Rich when cold, Choke Mode, this is called Open Loop since computer has no feed back from O2 sensors it is running fuel mix Open ended.

Thermostat should be 192degF model so ECT reporting 192-195degF would be good.
Climbing a long grade or pulling a load it can run 210-220degF.

oddball101 · Oct 26, 2015

Good to know about the motors regular and under load heat conditions. I still haven't gotten the P0117 to come back yet and I have been driving her just a little harder each day to test.

I did however see a pending code of P0455 - "Evaporative Emission Control Leak Detected (gross Leak)". It never actually posted and caused a check light or anything though so I am not sure if has resolved itself or not.

Still watching her like a hawk. Everything appears to be fine otherwise.

Thank you.

oddball101 · Oct 27, 2015

Just another update. No codes posting since previously stated, nothing pending either. I have to take some 2.5 hour drives soon so I imagine that will be a decent test.

Thanks for the good coaching!

oddball101 · Nov 2, 2015

Ya so I had an out of town trip that was about 3 hours each way. The P0117 code came back once on the way back. I believe it is heat related. When I put my valve springs in, I'll be going through and making everything all pretty under the hood. I most likely won't post back up here unless the code issue returns like it did previously in all of its frequency.

Now though, the code is manageable and not affecting gas. I was able to shut it off and it didn't return or the last 2.5 hours of the trip. I started cooling down significantly around that time which is why I think it was heat related, after it didn't come back.

Thanks again!

oddball101 · Apr 6, 2016

Annnnd it's back.

I read that running the wrong fluid (distilled water vs 50/50 antifreeze) can sometimes trip the P0117 code. I used water since I completed the swap because I didn't want to waste a bunch of radiator fluid trying to figure this out. My latest feeble attempt was to put the Peak (green) 50/50 in and it seemingly worked for about 2-3 months. Then out of the blue, it started popping back up again just like it had before.

It may be no coincidence that those were "effectively" the winter months here in SC too. Talk about frustrating.

Well, I begin my manual swap this weekend so while I am at it, I will be revisiting the wiring for the ECT connections again.

Don't know if I have already asked, but could a bad water pump cause issues like this?

oddball101 · Apr 7, 2016

Used that free "Torque" application yesterday to monitor temps on my android tablet. I can't say I trust the accuracy a whole lot, but the ballpark is there. It reported temps at or below 192* driving under 50mph. When I got on the highway, the temps then reported back and forth between 224-338*.

Still not seeing any bubbles in the coolant overflow and the fluid level appears to stay constant. As stated above, the code disappeared for 2-3 months after I exchanged the distilled water for the 50/50 green antifreeze. Now it is coming up daily just as it was before I switched the coolant to the proper type. WTF, over?

I am tearing into this when the weekend hits. Such an annoying problem.

RonD · Apr 7, 2016

Well at this point I would be OHMing out the wires for the ECT.

Either the 5volts coming into the ECT sensor is dropping as engine warms up or the Return wires voltage is dropping too much as engine warms up.

That last reading "224-338*" screams wiring problem.
Could be in the computer itself but check the external wiring first.

win · Apr 7, 2016

Personally, I have a fair amount of faith in the Torque app for direct ODB2 data. What Torque is reporting to you is very likely what the PCM thinks is going on.

Think you've ruled out the sensor so hidden wire damage, connector issue at (or IN!!) the PCM are likely suspects.

oddball101 · Apr 8, 2016

Well, the girlfriend flies home today for a couple weeks. Naturally, I'll be digging into my truck like its cool and hopefully I will finally find the problem being that I will have a second vehicle at my disposal.

I said that referencing the Torque app only because it was registering a few hundred rpm's lower than what the tach showed (albeit the stock tach isn't known to be 100% either), and occasionally it would tell me I was getting 58 miles to the gallon when decelerating. Overall though, I do have faith in the app. Its helped me a ton just getting general info and verifying my concerns.

I begin my manual swap tomorrow (m5r2) and while I am correcting the trans harness, I will most likely end up removing the intake and following up on every inch of the ECT harness back to the pcm if that is what it takes.

Thanks guys for your insights. Lets me know I am not crazy and it's good getting feedback to confirm some of my doubts.

RonD · Apr 8, 2016

You will get 50+ MPG when decelerating.
If in gear the engine acts as a brake, the braking part is the high vacuum created by throttle plate being closed when engine is still at higher RPMs.
And with fuel injection if your foot is off the gas pedal and RPMs are above 1,200 the computer shuts off the injectors, fuel savings not available with a carb, and your instant MPG will soar.

Injectors restart below 1,200rpm, but at idle levels, so instant MPG would still be higher, but depends on speed of course

oddball101 · Apr 13, 2016

Ok, so I am about 75% done with my m5r2 swap. After spending so much time under the truck over the past few days, I noticed what appeared to be a leak coming straight from the rear main seal area. I mean it's a line going straight down to the bottom middle of the dust pan and causing a slow drip. My buddy says it is actually coolant that has wound its way through the dirty engine area to where I see it now. He believes it is coming from the upper radiator hose as just below the thermostat he can see little spots of coolant. I really hope it isn't my rear main. Anyhow, between work and adulting after work, I will have to dig deeper this weekend.

We shall see..

oddball101 · Apr 25, 2016

Replaced the rear main as well as the oil pan gasket while the tranny was out by just slipping it up and around the pan itself. It was time consuming to clean the surfaces and mess with the bolts directly above the front diff, but other than that, it wasn't that bad. I wonder if it is possible to replace the oil pan gasket like I did with the motor in. Those two rear bolts seem like they'd be tough to get to.

Anyhow, the m5r2 swap is completed and in the process of looking for the oil leak, I found a small coolant leak which is good, and odd at the same time. Reason being is that I do not seem to be losing coolant from the reservoir, yet under the bypass hose on the thermostat, it can be seen where there is a small leak.

Hopefully addressing that will finally resolve these persistent frickin P0117 codes.

Troubleshooting help needed, P0117 won't go away.

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